The Mad Hatter, Superman has been duped by mind control before. for that matter Poison Ivy and Scarecrow also use a form of mind control that could be very effective.
anyone with magic powers or abilities (like Bat-Mite)
frankly the list is very long, (But not all inclusive) if it is written correctly. or with adequate Kryptonite access in Gotham.
@zeroplus: Joker could kill superman if he wanted. Scarecrow would scare Superman and play mind games with him. Poison ivy can control him like she did before. Ra's al ghul could take him with prep
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