Numerous places! Believe it or not, the big chain
Cabinet Knobs stores have some interesting knobs and pulls. I'll add some links for interesting ideas below. You know, the trouble is not finding knobs as much as picking the ones you like the most. Have fun!
Prima Cabinet Knobs is a professional manufacturer and supplier for granite knobs and pulls, cabinet handles ,stone door knobs. Your source for kitchen cabinet hardware at discount prices.
Website:
http://www.primacabinetknobs.com/