Elle/Sylar, Elle/Claire, smart and kinky...

Can't promise you that you won't find spoilers in any of these recs. Best bet is to scan the header to make sure nothing's ruined for you...

I'm gonna send you to dragynflies, ashesfor_trees, and supperkappa first. They're all great with both pairings you mentioned. mrstater also writes some really Sylar/Elle sweet stuff.

For a few more Sylar/Elle stories that really rock my socks, try these:

Someone Else's Heart Pumping Someone Else's Blood
The Five Times Sylar and Elle Killed and One Time They Didn't
For You/For Me

I also like ever_obsessed's Elle/Claire stories. I'll have to get back to you on specific minor character recs, but if you might want to check drive_thru_rxfor all sorts of characters.

P.S. If you aren't using your powers for evil or for sexy, then you're doing it wrong.