Villain Dr. Light started out as a formidable foe capable of taking on the Justice League single-handed but was a victim of severe Villain Decay in the Bronze Age and Post-Crisis eras, mostly notable for being repeatedly defeated by kids. And while defeat at the hands of the Teen Titans isn't all that shameful, he was also humiliated by Little Boy Blue and the Blue Boys, a team of non-powered pre-teens! That all changed with his rape-the-wife moment in Identity Crisis (2004).
The entire Injustice League, which consisted of Major Disaster, Cluemaster, Clock King, Big Sir, Multi-Man, and Mighty Bruce. Individually, they were talented in some area, if lacking in others. As a group... they're still a bunch of losers. Here's how bad their luck is — while staying in Europe, they happened to attend the same French as a Second Language class as the Justice League. And this was following a bank robbery that was thwarted by the fact that none of them could effectively communicate the idea of "This is a stickup" in French. They ended up pulling a Heel–Face Turn and joined the Justice League as their Antarctica branch.
Bolphunga the Unrelenting is a Large Ham villain, notable for using an axe against power-ring wielding space cops, and for attempting to take on Mogo.
Larfleeze is implied to be capable of taking on the collected Guardians of the Universe, has natural abilities allowing him to stand his own against entire armies, and has had a billion-year-old enemy create an entire artificial star system as part of a plan to defeat him. He's also so short-sighted and gluttonous that he spent most of recorded history squatting and eating in a tiny corner of a planet that evidently didn't know he was there.
Rainbow Raider became this, once going so far as to attend a villainy motivational seminar in a futile effort to stop losing all the time. Neron once sent him an invitation to his upgrades-for-souls meeting just so the Trickster could steal it from him.
The Rogues in general play with this trope, since for the most part they're not very hardcore criminals, at best committing bank robberies, and having funny gimmicks like a cold gun, a bunch of toys, a 'mirror gun', and ice skates that make their own ice. They've also commonly been depicted as blue-collar types who got into supervillainy because it was the best work they could find or have some other sympathetic quality like being mentally unwell or an abusive childhood. However, they avoid being ineffectual; besides managing to give Barry Allen, the Silver Age Flash, constant grief, they'd even still be able to fight evenly against his Superior Successor Wally West. In Identity Crisis (2004), Wally even calls out Batman for assuming that this trope was in play, after Captain Boomerang (who is not this trope in either way, being a highly competent Jerkass) kills Robin's dad, since as Wally notes, Batman is angrier that it was a villain who he considers a joke rather than someone like the Joker or Two-Face. Notably, the Rogues became heroes for a while, and though C-listers at best, they were often shown to be very good at it.
Two minor Animal Man villains, Red Mask and Time Commander, play this trope for drama. The former never wanted to be a supervillain but after he got his death touch powers, he did it just because he had nothing else he really could do and ended up not even being a very good villain. The latter tried to use his time warping powers to bring back dead loved ones, but a side effect of these powers made other historical anomalies appear, leading to the Justice League of Europe having to defeat him.
◊, who Huntress made quick work of.
