If you mean characters that are featured on both Heroes Wiki and Villains Wiki, I can think of some right off the bat:

Cruella de Vil (Emma Stone)

The Grinch (Bendict Cumberbatch)

Bumble

Heat Miser

Snow Miser

Frankenstein's Monster (Universal)

• Venom Snake

• Big Boss (Metal Gear)

• Vaggie

• SCP-343

• SCP-049

• The Intruder (Poppy Playtime)

• The Chosen One (Animator vs. Animation)

• Yeti (cryptozoology)

• The Puppet (Five Nights at Freddy's)

• Vanny

• Gregory (Five Nights at Freddy's)

• Lusamine

• Kafka

• Junko Enoshima

• Paz Ortega Andrade

• Omori

• Aubrey (Omori)

I can only remember this ones.

Bender

Lobo

Alucard (or his Twitter account in Hellsing Ultimate Abridged, TheCrimsonFucker.)

Also, Shadow.

Basicly every team fortress 2 mercenery

Frisk(undertale)

Flowey(undertale)

Darth vader

• Vaggie

• Suguru Geto

• D-16 (Transformers One) (but he is Megatron as a villain)

• SCP Foundation

• Choso

• Zuko (Avatar)

• Loki Laufeyson (Marvel Cinematic Universe and L1130)

• Sylvie Laufeydottir

• Alastor (Hellaverse)

• Cherri Bomb (Hellaverse)

• N (Murder Drones)

• V (Murder Drones)

• Anakin Skywalker (Star Wars) (but he is Darth Vader as a villain)

• Deadpool (Marvel comics and X-Men Movies)

• Rick Sanchez

• Every TF2 classes

Cut Man

Time Man

Guts Man

Elec Man

Ice Man (Mega Man)

Fire Man (Mega Man)

Oil Man

Bomb Man

Bass (Mega Man)

Treble

Splash Woman

Rohan Kishibe

Yuya Fungami

Weather Report

Diego Brando

Oliver (Fire Emblem)

Gangrel

Walhart

Edelgard

Hubert

Ivy (Fire Emblem)