The 100 Girlfriends Who Really, Really, Really, Really, Really Love You: Due to her Number Obsession, Suu Hifumi regards numbers as real people to the point she holds genuine affection only for them before falling in love with Rentarou. Her first crush was the numbers 1, 2, and 3 on the victory podium at a sports day in kindergarten, and regards a number 7 on her jacket as a childhood friend. Her seeing numbers as people is so strong it makes her incompetent at math, as to her 1 + 1 should be 11, not 2, since it's a pair of 1's.
Seravy from Akazukin Chacha has a ventriloquist doll named Elizabeth. They're a couple.
The Angels in Angelic Layer. If you hear "it's just a doll/toy/robot", you know that person needs a dose of The Power of Friendship, despite your parents probably thinking they have a valid point.
In the earlier parts of the Golden Age Arc, we see Guts as a child being taught how to use a sword. He uses a two-handed blade which is considerably oversized for a kid. We later see him hugging that sword like a teddy bear while he's going to sleep. Considering that he was raised in a mercenary band, blamed for the death of the only mother figure he ever had, and the abuse he suffered from the guy he considered a father figure, it's not too far fetched to believe that for Guts the sword was his only friend at that time.
Guts is often visibly shown having trouble sleeping without a sword and claims that he can't relax without it on hand. Considering the dangers he faces, this concern is probably for more practical reasons, but who's to say whether the possible emotional and practical reasons can't complement each other?
Played for laughs with Puck and the Behelit Guts carries around. Despite it being an Artifact of Doom, he affectionately calls it "Betchi".
Something of a subversion with the Soul Reapers' Zanpakuto swords. Each sword is part of the Soul Reaper's being, but also has his/her own spirit and name. We rarely see a Zanpakuto's spirit (Ichigo's Zangetsu (Both ofthem) usually only speaks to him in his own mindscape, Renji's Zabimaru and Mayuri's Ashisogi Jizo only appear a couple of times, and Yachiru's true identity as Kenpachi's Nozarashi isn't revealed until the final arc), but all the main Shinigami/Soul Reapers have learned their swords' names. While the swords are rarely treated as characters, in one episode Yumichika gets so mad at his that he beats him against a rock. Rangiku's sword Haineko kind of rubs her the wrong way, too.
Any remaining elements of this are thoroughly thrown out the window in one the anime's filler arcs, where all the Zanpakutou spirits are materialized in humanoid forms and wreaking havoc. In the same arc, the Zanpakuto are given even more human traits; like Yumichika's Fuji Kujaku refusing to reveal his true power because he feels insulted when he calls him that. (For reference, his actual/Bankai name is Ruri'iro Kujaku.)
Played straight in a later arc, in which having a companion cube causes it to have certain powers, such as a dollhouse which lets you trap people inside of it, or boots that make your kicks increasingly lethal as they get dirty.
In Carnival Phantasm during the Grand Prix episode, Assassin displays extreme affection for the temple gate, even to the point of jumping out of a truck in a vain attempt to save it when Bersercar knocks it over a cliff.
The lizard Ellis picks up in episode 3 of El Cazador de la Bruja is hardly an inanimate object, but the only thing it does in the entire series, aside from belch in Nadie's face, is crawl away in the end.
For Goku, the Si Xing Qiu (aka 4-star Ball). He believes his grandfather's spirit resides within it, going as far as calling it grandpa at several points, and is very protective of it. He refuses to give it to Bulma, which is how he ends up going on a quest with her, and most of the Red Ribbon Army Arc revolves around him looking for it. He even gives the keepsake to his son (sown into a hat).
Kinto'un, or Flying Nimbus as it's called in the English dub, also gets this treatment. While being a magic cloud, it doesn't appear to be any sort of living, thinking creature, but Goku still often talks to and treats it like it was one of another one of his friends. In the manga, the only time it is shown to have a reaction SFX is when Gohan has a race contest against it.
Dragon Ball Super: Future Trunks's sword is revealed to be this for him. Despite him not needing it, as he's already capable as a fighter without it, having it on hand calms him down. He ultimately defeats the Arc Villain with it by letting it absorb the power of a Spirit Bomb into it, creating the technique called "Sword of Hope".
Tohru Honda from Fruits Basket rarely goes anywhere without a photo of her deceased mother Kyoko on her person, going so far as to take baths with the photos and treating them as though they actually are Kyoko. In the first episode alone, she has a Freak Out over her mother's picture being buried in a landslide alongside her tent, speaking as if Kyoko herself was Buried Alive, and when Hiro takes her wallet, which contains one such picture, she reacts as if Hiro just kidnapped her mother. Deconstructed as time goes on, as it's made clear that Tohru doing so is unhealthy and signifies her inability to accept her mother's death and move on.
In one episode of Full Metal Panic!, Sosuke is coaching the lousy school rugby team. He makes them go through physical and mental training from hell. At the end of the training, he gives each of them a football and makes them assign female names to them. Cut to one of the football players caressing his ball saying, "Don't worry, baby. I won't be rough. I won't hurt you" with a mentally disturbing smile and crazy eyes.
A Running Gag is for the characters to act as though Shinpachi isn't a human wearing a pair of glasses, but rather a pair of glasses wearing a human (which is taking a jab at his status as The Generic Guy). If his glasses are removed, it's practically guaranteed that everyone in the vicinity will start paying attention to them instead of him. It's actually worked to his advantage on a few occasions, allowing him to escape notice from enemies and sparing him from a genderbending satellite (it only targets his glasses, which turn pink), though he complains about it regardless.
Hasegawa also gets this treatment with his sunglasses from time to time, though not nearly as often as Shinpachi.
In Gravitation, there's Ryuichi's Kumagoro, a stuffed pink rabbit that he treats like a person, and even provides a voice for. There's some speculation, though, as to whether this is real or simply an act put on by Ryuichi.
Great Teacher Onizuka: Tomoko is a Lonely Doll Girl because of her Friendless Background (though she doesn't treat them as actual people, more like something she can use for a Surrogate Soliloquy). Onizuka connects with her by playing dolls together, communicating through them at first rather than talking to her directly. In the Live-Action Adaptation she makes a duck puppet called Dakko that she talks to Onizuka through, and has an improv conversation with at the pageant.note In a bit of Fridge Brilliance, "Dakko" is not only the Japanese pronunciation of the English word "duck", it also means "hug".
Seems to be quite common in the Gundam series. Usually it starts with the pilot pleading with the Gundam to keep going during an especially tough battle, but in can escalate to them asking the machine for advice and then acting like advice has been given. Particularly, in Gundam Wing, all of the characters who pilot Gundams will talk to their machines at least once every couple of fights. In an early episode,when Quatre's about to blow up his own Gundam, Sandrock, the cockpit opens by itself, causing Quatre to wonder: "Are you telling me to get down, Sandrock?" A few of the suits also have the ZERO system, which tends to inspire insanity in the pilots who use it. That sure doesn't help.
Ikaros and her watermelons in Heaven's Lost Property. She is fascinated by watermelons and tends to carry one around with her. It's gotten to the point where she is growing a watermelon patch in her backyard and taking care of it like one would take care of a litter of puppies or kittens.
Mako: You gave your uniform a name? Boy, you must be pretty lonely to do that!
Yui Hirasawa from K-On! is shown to be strongly attached to her guitar, a Gibson Les Paul which she named Giita. She initially chose it because she thought it was cute, and is sometimes shown sleeping with it and dressing it up. In fact, side character Himeko at one point mentions how she loves it as if it were a boyfriend.
Several times the characters talk to or about Mazinger-Z and Fem Bot Aphrodite A like if they were sentient beings. Sayaka actually has a Heroic BSoD when Aphrodite A is destroyed. She even hallucinates that Aphrodite is calling her. And then you have Minerva-X, an actual sentient Fem Bot and Humongous Mecha that can act, think, and feel on her own and was programmed to be in a Battle Couple with Mazinger-Z, and considers Mazinger to be her Companion Cube (as Sayaka protests that only Aphrodite is allowed to be Mazinger's partner).
Yamada the rock has gained a lot of respect for a small stone.
Chiaki's teddy bear Fujioka (at least in the first season). She talks to it quite often and viewers can only hazard a guess as to whether its reactions are real or all in Chiaki's Ahoge.
Molester Man sometimes acts as if "Sachiko", his onahole, is a real girl.
My Dress-Up Darling: Male lead Wakana Gojo often talks to a Hina doll head made by his grandfather, owing partly to his lack of friends.
One Piece: The Going Merry is treated as another member of the crew by the Straw Hats. It later turns out to be semi-sentient, as it's inhabited by a Klabautermann (a water spirit that aids sailors), which causes its eventual destruction to be one of the biggest Tear Jerkers in the series.
Nekozawa's hand-puppet Beelzeneff is part of his club.
Tamaki has talked to his teddy Kuma-chan as if he were real, as has Honey with his stuffed pink rabbit Usa-chan.
Rurouni Kenshin: Saitou, during his (manga) fight with Kenshin, evades Kenshin's attempt to break his sword, stating that it has kept him safe since the revolution, and that he isn't about to let anyone break it. Later in the fight, Kenshin tries again, and lops it in half.
Futaba from Seiyu's Life! has a plushie of Korori, the main character from her favorite childhood anime, whom she treats as a source of advice and comfort and occasionally voices. Korori also acts as the series mascot and narrator, providing information about the voice acting industry for the audience.
Shirobako has a Miyamori's two dolls Mimuji and Roro. Like Korori above, Miyamori often voices them and talks and pretends that they talk to her as her Good Angel, Bad Angel, to the point that where we see her speaking in their voices when they aren't present. And like Korori, the two of them act as the show's series mascot and explain to the audience the industry's inner workings.
When Eiko's Famicom breaks down, she's brought to tears, calling it her old buddy; it's been with her since childhood and was there for her through happy and sad times alike, and is "like family" to her, to the point where she buries it in the garden, complete with grave marker.
Ika treats an umbrella she's given with a similar reverence, and is equally devastated when it's blown out of her hands and destroyed by a passing car.
Strawberry Panic!'s Kagome has a teddy bear named Percival that she treats like it's alive. Being very shy, she tends to channel her feelings through the bear. After a random act of kindness from Nagisa, Kagome asks Percival "Was that a friend of yours?"
In Sumomo Mo Momo Mo, Tenka has a soccer ball that he named Becky. She talks to him, and he often asks her for advice. She actually gives pretty good advice, too, considering she's a soccer ball...
When LLENN of Sword Art Online Alternative: Gun Gale Online gets particularly stressed in battle, she begins to imagine her P90 submachine gun, "P-chan", speaking to her and promising to help protect her. The gun's destruction in battle sends LLENN into a vengeance-fueled Berserker Rage.
In Tamagotchi, Melodytchi takes her Melody Violin everywhere she goes and calls it "my friend". It later turns out that the violin is not only as old as Melody Land (Melodytchi's home) itself, but it's also sentient.
Satou, the hikikomori protagonist of Welcome to the NHK, often hallucinates that the appliances of his apartment are talking to him and has long conversations with them. While the light novel and manga implies that the cause of this is the use of designer drugs, the anime plays it as a delirium due to Satou's social isolation.
In Yo-kai Watch, while in Alcatraz, Manjimutt gets a teddy bear during the prison's annual distribution, which he calls Sam. Due to his loneliness, Manjimutt deludes himself into thinking that Sam can talk and eventually walk, and only snaps back to the reality that Sam's a teddy bear when Sam's head gets ripped off during an jailbreak attempt.
The cards themselves in Yu-Gi-Oh!: Duel Monsters fit the bill. Whole "Heart of the Cards" thing and all.
The tree that adopted Spectre (from his perspective) in Yu-Gi-Oh! VRAINS, as he considers it to be his mother figure, and does not take it well when it gets chopped down. Furthermore, he also starts treating his Sunvalon cards in much the same way, especially Sunvalon Dryatrentiay.
The Vulcan 300, a "toy robot" made from a pocky box, in Zatch Bell!, whom only Gash considers an actual person.
