Batman is one of the greatest heroes of the DC universe and he has enemies that match their foe's title. Even so, there are many underrated villains that not everyone has heard of. But today, I'm going to show you what you've missed, as these villains are simply great.
LET'S DO THIS!!!
Kirk Langstrom was a gifted scientist whose specialty was the study of bats. In an attempt to gift humanity with bats’ sonar abilities he created a serum that was meant to do so. However because he was going deaf, he decided to test the serum on himself. The serum worked, but there was a little side effect: He was turned into a giant monstrous bat himself! Now, Langstrom haunts the night as the hideous Man-Bat desperate in search for an antidote to cure him. - Whatculture.com
Garfield Lynns was originally a pyrotechnic expert who used to commit petty crimes. He was a pyromaniac, however and soon began to use dangerous pyrotechnic equipment such as flamethrowers and grenades in his thefts. During one of his robberies, he set fire to a chemical factory that raged out of control and scarred him heavily. Therefore he built his fireproof suit to protect himself, continuing his fire related crimes as Firefly.
Owlman is a name held by several characters in the DC Universe. These include Roy Ramond and Thomas Wayne Jr. Owlman is a member of the Crime Syndicate, which is essentially a super-villain version of the Justice League. In some interpretations, the Crime Syndicate has taken over a parallel Earth and planned to destroy “our” Earth. Each member of the Justice League had their own counterpart. In Batman’s case, it was Owlman. Owlman was created as an evil counterpart to Batman due to the fact that owls prey on bats. The Owlman I’m referring to is the evil counterpart from a parallel Earth who Batman has had to fight on some occasions.
4. THE MAD HATTER
The Mad Hatter is one of Batman's enemies. He is psychotic and has an obsessive-compulsive disorder. His main weapons are mind controlling devices. He is very short standing about 4'8 inches and weighing 149 pounds. - Comicbookmovie.com
5. KILLER MOTH
A villain obsessed with moths who tried to kidnap Moira Queen during the Gotham blackout. He is not so well known because...he...doesn't do much.
Lynx is the right hand of King Snake and new leader of the Ghost Dragons, a Chinese gang comprised of younger members. Lynx is another supposed "love-interest" for Red Robin.
7. JUDSON CASPIAN
A wealthy socialite and violent vigilante known for wearing...leather armor? He is also known to be another version of The Reaper.
8. PROFESSOR PYG
Pyg is the leader of The Circus of Strange, and previously an agent of Spyral. Batman (Dick Grayson) first learns about Professor Pyg when he captures his minion Mister Toad. Pyg proclaims the "Year of the Pig," and he and his Circus of Strange appear in Gotham City as part of the plan of Dr. Hurt. Pyg starts a campaign to make people "perfect," and his minions capture Robin (Damian Wayne).
9. CALENDAR MAN
Calendar Man is fascinated by dates and calendars; even his real name is a pun on the Julian and Gregorian calendars. Just like The Killer Moth, he is also very rarely found in any comic books.
10. MAD DOG
Mad Dog was trained as a young boy by David Cain to be the next generation of the League of Assassins but broke down and killed all the other young assassins. Ra's al Ghul decided to kill him, but he escaped and later would be brought into the League by Nyssa al Ghul. - Comicvine.com
11. CORNELIUS STIRK
A delusional serial killer that feeds on people's hearts to survive and has the psychic ability to make people see him as someone else.
Magpie was a cleptomaniac, serial killer, jewel thief and first villain at Batman and Superman team-up in New Earth. - Comicvine.com
Oh! And I also found this...
Kai was the best student in the Armless Master's dojo in Gotham City. Kai was also a thief, which brought him into conflict with a young Selina Kyle, who "tainted" a religious ceremony he was performing by touching a religious artifact depicting Bast that he had intended to steal himself. After Kai severely beat her for her interference, Kyle followed Kai back to the secret dojo, where the Armless Master welcomed her as a student. She began studying, and quickly showed Kai up in front of his master. Kai soon learned that Selina had taken on the identity of Catwoman, and, in religious zeal, took it as a sign. Adopting the identity of Hellhound he attempted to force Selina to kill him, believing this would finish the ceremony she had interrupted when they first met, and that he would be reborn as a "true hound of hell". Catwoman scarred his face instead, deepening his already great hatred of her. Kai always refers to Selina as Nehko-Chan. - Wikipedia.org
Well guys, that's all for now. There are many other Batman villains that deserve to be in the spotlight but unfortunately are not. Remember that I don't dislike any of them. I actually had a crush on Killer Moth, Firefly, Magpie and Man-Bat.