Exculding abstracts/omniscient characters because they have an unfair advantage
Cho for pure calculation
I think Valeria said she surpassed her father in terms of intelligence so Reed is no longer top pick but still in top 10
Braniac is up there in any of his incarnations.
Superman as well if you want to go by some of his more asshat crazy inventions. CA armor the helmet/hat thing that split him into two supermen the wish machine. none too shabby neh.
Doom is up there
I would say Kang but most of his intelligence and resources come from him living in the future but he's not too shabby.
Kid Omega for the billions of brilliant thoughts per second.
Banner and Pym definitely
I'd say Ultron surpasses Tony in Robotics
The Ancient One/Nabu/Shazaam for mystic arts
Batman is more of a tactics kind of guy rather than an inventor. He just tends to have multipurpose devices handy.