Is it quirky character based novels that you're looking for specifically?
I'd agree with southeast's suggestion of The Rosie Project by Graeme Simsion. The central character has Aspergers but it is often played for laughs. I didn't like the sequel The Rosie Effect, which was disappointing.
Iirc, you weren't keen on Eleanor Oliphant, southeast? We normally agree on books, but perhaps we can agree to differ on this one? Another suggestion might be The Curious Incident of the Dog in the Night-time by Mark Haddon or Rubbernecker by Belinda Bauer, both of which fit the quirky outsider type character novel. Or perhaps A Boy Made of Blocks by Keith Stuart.