Technically, he’s a Human Torch villain since he first appeared in Strange Adventures when it was Torch’s solo book…er…but then so didthe Wingless Wizard. Um. Fenris rolls a saving throw vs weasling—fails! 
Minor nitpick: Paste-Pot Pete, a/k/a the Trapster, first appeared in Strange Tales #104. Strange Adventures was a DC Comics title.
But I’m with Fenris, I vote for the Flash’s rogue’s gallery. I vaguely recall in ‘70s pre-Crisis Flash comics, the gallery would hold annual meetings and awards ceremonies for villainy. I don’t think any other hero or groups’ rogues did anything like that.
You know if you hadn’t said on a regular basis - I would throw the Authority into the fray. They’ve got some great (albeit one-time) villains:
Kaizen Gamorra
God
the evil Doctor
Regis (Sliding Albion)
the Americans
Dr. Krinstein
the High
the United States of America
and of course … the original Weatherman Henry Bendix.
Not too shabby, I’d say.
- Peter Wiggen
A slight hijack.
Those of you who mention the Flash’s villains’ tailor, did you know there’s a similar one in Gotham City? The difference is, he also does tailoring for Batman. However, the story I read this in is a novelization and probably isn’t cannon.