An out-of-universe one is the fact Warren Publishing managed to successfully resurrect horror comics by Loophole Abuse. The Comic Codes Authority had destroyed them and forbid the use of the supernatural but Vampirella was a magazine not a comic.
Harris Comics
How Vampirella kills Hemorrhage in Vampirella Lives. She hypnotises him into drawing blood from every vampire in the area which leaves him weakened enough for her to kill him. Then she she sends his corpse to his mistress Nyx with the words "I live" written on his chest.
The first issue of Vampirella: The New Monthly has Vampirella facing a group of American Civil War era vampires who outnumbered her and had superior experience. Vampirella comes prepared, however, and has a priest bless the rain turning it into holy water. Since she is immune to traditional vampire weaknesses, she survived but her foes don't.
Pantha showing herself as a guile hero in her side story. She deliberately gets captured by Midwinter with a fake Scarab of Atum Ra. The real Scarab was left in Dixie's apartment while the fake one turns out to be a bomb.
Vampirella killing Nyx.
2011 Dynamite Series
In the Crown of Worms arc, Vampirella manages to effortlessly own virtually everyone who attacks her, no matter their level of competence or strength. This includes vampires, Dracula's former bride, and Vampirella herself. Sadly, it doesn't cause any of them to realize how outmatched they are.
In the same arc, Vampirella successfully match will for will with an Eldritch Abomination who plans to use her as his body for entering the world.
In A Murder of Crows, she finds herself against a group of seemingly invincible masked crow-themed demons who are each her match in physical power. Vampirella, using tactics and cleverness, delays them each until she can deduce their weakness. Their masks bind them to this reality.
In Inquisition, Vampirella is confronted with the entirety of the Cestus Dei led by the traitorous Herr Schuld who betrayed her and got Sofia killed. Vampirella lets him and the Cestus Dei know exactly what she thinks of them and their ends justify the means mentally. Then she proceeds to slaughter them all.
Vampirella also successfully assembles an army of ALL of her friends across forty years of continuity to repulse Dracula's army.
2016 Dynamite Series
Vampirella is faced against a genuinely immortal Slade who is her equal in both combat as well as supernatural strength. Vampirella proceeds to drain her of all of her blood then pickle her, leaving nothing more than a trophy for her former slave.
