Frisk knows: Sit, Lay down, Bang (play dead), Shake Hands, Rollover, Up, Down, Stay, and a few others, though I don't really count those since he's a bit rusty.

Ethan knows: Sit & Laydown and Stay, but only partially. He has a hard time learning tricks. :\

Skylar knows: sit and shake hands. My sister *thinks* he knows laydown, but he won't laydown unless you make him follow the treat, and in my opinion, he hasn't fully learned it.