I can't believe I forgot Prometheus. He should definitely be in the top 10. He's a better engineer than Batman and his suits are extremely haxx (See the one he built for Afterthought).
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Defense against someone like Ray Palmer (please log in to view the image) (please log in to view the image)
Bullets to stop Kryptonians (please log in to view the image)
Stop Speedsters (please log in to view the image)
Telepaths (please log in to view the image)
The Justice League and it's various members (please log in to view the image)
Lord Havok somehow destroys/kill Dreamslayer (DC's version of Dormammu). Dreamslayer is laced with microscopic black holes and has near infinite space in his cells, according to Ray Palmer.
Enter Tom Strong. Now apart of the mainstream DC Universe. He might enter the top 20 list. Him discovering the Dark Multiverse before everyone is pretty impressive. Eat your heart out Batman.
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Nah, because of actual feats. Even Batman said CURRENT Tim is smarter than him (Which is why he hired him in the first place). Future Tim has tech and feats far beyond Batman and even Lex.
Right, he's the flavour of the month. There's always something bigger and badder. Next event, there'll be someone that'll make that Tim look like a chump.
I mean, the guy has spent a lot of time as a bit of an author avatar, a "anything Batman can do, I can do better", and this was just the natural escalation of that combined with him being the fun thing to do this event.