Im sorry I can't add pictures because I'm typing this from my iPod but I'll add the lookalikes names and you can look them up :)
* means that they look nearly EXACTLY like their lookalikes
Javier Bardem looks EXACTLY like Jeffrey Dean Morgan (John Winchester)* Also Robert Downey Jn.
Jared Padalecki(Sam Winchester) apparently looks like Nick Wechsler (im sorry ealier on I wrote he looked like Neil Wechsler by accident lol, if u want to end up in hysterics search neil wechsler up lol)
Jensen Ackles (Dean Winchester)-link
and Emilio Eztevez (only a teeny bit though)
Samantha Ferris (Ellen Harvelle)- Paget Brewstar
Alona Tal (Jo Harvelle) - Bridgit Mendler*
Chad Lindberg (Ash) - Giovanni Ribsi
Samantha Smith (Mary Winchester) - Robin Wright*
Misha Collins (Castiel) - I've always thought he looks like Bruno Mars.
Lauren Cohan (Bela) - Rachel Blakely (thank you shomill :))
When I find more look alikes I will add more :)