For electric blues I like my Blue Chip TD45 (I keep some heavy dunlop primetones in the gig bag in case I ever lose it). Had it several years, only left it at a gig once (drove back the next day to get it). It is slick and quick on the strings, yet sticks to my fingers, even sweaty.
On the flat top, for bluegrass and fiddle tunes, I prefer a heavy triangle pick. I have 2 real tortoise shell and a Charmed Life "brown" that I will use going forward since TS is endangered. The TS really bring out the tone and crispness needed for flat picking.
Honestly, in a pinch, a Fender heavy or Dunlop 1.0 work fine, they are just a little slower.
I have never been able to get speed and accuracy with a thin or medium pick on anything. They do not snap back fast enough, which actually slows you down. They just sound sloppy. YMMV