....even Mr. Freeze, Mad Hatter, Ra's Al Ghul, Two-Face, Man-Bat, Bane, Killer Croc, Poison Ivy, Deadshot, Killer Moth, Firefly and Scarecrow have gotten fans over the last decade or so...
....but, there are villains even more obscure to learn about!
Teen Titans first, first faced Crazy Quilt in Batman #316 (October, 1979 by Len Wein, Irv Novick and Frank McLaughlin), with a similar origin and having been put in jail by Robin before, and that Crazy Quilt returned a few times, in Batman #368 (February, 1984) and Detective Comics #535 (February, 1984) to face Robin (Jason Todd), part of a mass escape in Batman #400 (October, 1986), and popping up in crowd scenes (like in Underworld Unleashed #1 and JLA #34) before a new, female Crazy Quilt took over in during the Villains United mini-series.
Mr. Polka Dot
This was it for the Zodiac Master....
....having no known relation to other Zodiac based villains, such as Doctor Zodiac or Madame Zodiac (who faced Superman, Batman and Batgirl over their careers.....).
Batman disguises himself as a criminal to hire the Eraser, who recognizes Bruce Wayne, and captures him (as the Eraser is Bruce's old school chum of Lenny Fiasco). This forces Robin into action to distract the Eraser, as Bruce escapes the Eraser's trap, changes into Batman, and rubs out the Eraser's freedom.
original Starman, Ted Knight, after giving his soul to Neron in Underworld Unleashed #1 (November, 1995), and sparring with Ted Knight in Starman #13 (November, 1995), being their for Ted's final battle in Starman #63 to #71 in 2000, returning to face Batman again (starting with Detective Comics #825), as well as Batgirl, Stephanie Brown (in Batgirl #6 and #7 of 2010).
Magpiefirst meetings in Man of Steel #3 (November, 1986 by John Byrne and Dick Giordano).
Magpie returned to face Batman and Robin (Jason Todd) as unrest grew towards super-heroes (even the ones in Gotham) in Batman #401 (November, 1986). Magpie didn't take advantage of Neron's offer in Underworld Unleashed #1, ending up in Arkham Asylum, and dying in Batman #651 (May, 2006).
...and was defeated by Batman when the Caped Crusader stole the villain's powers magnetic powers, and used them against the villain!
The 1960s were a weird time for the Batman....
the Outsiders, starting in Outsiders #21 (July, 1987 by Mike W. Barr and Jim Aparo), being defeated in Outsiders #22 (August, 1987), and waiting all the way until Infinite Crisis #7 (June, 2006) to appear again!
The lady who would become Mime took to a more artistic life, first ballet, then mime, all while trying to live a quiet life. That life wasn't too successful, so, the Mime took to crime, using a gun (with a silencer), to commit crimes (and keep the noise down). This caught the attention of Batman and Robin (Jason Todd), who stopped her while she was attempting to silence a rock and roll concert (with the feedback of sound deafening the girl), all in Batman #412 (October, 1987, by Max Allan Collins, Dave Cockrum and Don Heck).
TarantulaTarantula, Jonathan Law), with her first appearance in Nightwing #71 (September, 2002, by Devin Grayson, Rick Leonardi and Jesse Delperdang). Catalina admired Tarantula, taking on the identity to fight the crooked cops of the city in Nightwing #75 (January, 2003). Tarantula is a bit brutal in her enforcement of the law, but she has reason to be, as John Law (along with many other residents of Dick Grayson's apartment building) are killed by Blockbuster in Nightwing #89 (March, 2004), leading Tarantula to kill Blockbuster in Nightwing #93 (July, 2004), with Nightwing failing to act to stop her. Nightwing goes on the run with Blockbuster for a time, turning her in in Nightwing #100 (February, 2005). Appearing next defending Bludhaven from OMACs in Robin #143 (December, 2005), she becomes one of many villains looking for redemption in Secret Six #1 to #6 (2008/2009), stealing a "get out of hell free" card from Neron, but sacrificing herself to stop Junior (the sister of the Secret Six's Rag Doll).
....along with Tweedledee and Tweedledum (who had been Batman villains prior to this as well, as had the Mad Hatter), and newer villains like the Lion, the Unicorn, the Walrus and the Carpenter.
Captain Boomerang and Hawkman's Gentleman Ghost, or Green Arrow villains like the Clock King). After all, at one point, even Deadshot, Scarecrow and Poison Ivy were barely used villains.