Who are all of Batman's enemies?

The Joker
Ra's Al Ghul
Two Face
Mr. Freeze
The Riddler
Scarecrow
Bane
Clayface
The Penguin
Killer Croc
Hush
Poison Ivy
Catwoman
Harley Quinn
Lady Shiva
Prometheus
Zasz
Black Mask
Brother Eye
The New Red Hood

Joker
Penguin
Catwoman
Riddler
Two-Face
Poison Ivy
Mr. Freeze
Bane
Scarecrow
Ra's Al Ghul
Zsasz
Baby Doll
Spellbinder
Hugo Strange
Killer Croc
Harley Quinn

-The common street thug who murdered his parents
-The Joker
-Ra's al Ghul
-Ra's al Ghul's son
-The Joker
-Harley Quinn
-The Riddler
-Two-face
-Great White Shark
-Mr. Freeze
-Poison Ivy
-The Penguin
-Scarecrow
-Boss Falcone
-Boss Maroni
-Clayface
-Hush
-Catwoman
-Killer Croc
-Ventriliquist & Scarface
-KGBeast
-Zsasz
-Amygadala
-Bane
-Black Mask
-Solomon Grundy
-Maxie Zeus
-Man-Bat
-Firefly
-Killer Moth
-Everywhere Man
-Hugo Strange
-Shadow Thief
-Sinestro
-Spellbinder
-Orca
-Tim Drake (under Joker's control)
-Harley Twins
-Holiday
-The Hangman
-Calandar Man
-The Monk
-Lady Shiva
-Cassandra Cain
-Anarky
-Blockbuster
-Deadshot
-Mad Hatter
-Headhunter
-King Snake
-Lynx
-Prometheus
-Red Hood
-Torque
-Phantasm

Check the Arkham Aslyam registry.

Joker
Harley Quinn
Catwoman
Killer Croc
Penguin
Mad Hatter
Riddler
Bane
The Ventriloquist
Scarecrow
Anarky
Black Mask
Blockbuster
Calender Man
Catman
Clayface
Two-Face
Cluemaster
Deadshot
Firefly
Hugo Strange
Joe Chill
Hush
KGBeast
Killer Moth
Man-Bat
Maxie Zeus
Mr.Freeze
Mr. Zsasz
Poison Ivy
Ra's Al Ghul
Red Hood
Solomon Grundy
Tweedledum and Tweedledee
Big Top
The Gentleman Ghost
Clock King
Copperhead
Crazy Quilt
The Key
King Tut
Kite Man
Mr. Polka-Dot the Polka-Dot Man
Mirror Man
The Mole
Magpie
Roxie Rocket
Orca
The Phantasm
Prometheus
Spellbinder
The Spook
Tiger Shark
Zebra-Man
( let's just say there's TOO many Batman villains LOL XD)