You will have to notch/grind the inside rear corner of the right side peg to clear the brake pedal on fold up with any peg. Anything for a Yamaha YZ fits.
Yep! Almost anything Yamahaish. I pulled the pegs off my 2004 WR250F and they slid right on it.. But as Glenn has said you need to make sure they have enough clearance to pivot back on the right where the brake pedal runs. I try and look for ones that are easy to grind or cut and will still have good strucural integrity afer doing so. Can't remember what brand I have on now but they're good Can find out for you.
I ran the Moose hybrids (big, stout pegs) with a fair bit ground out of the rear inside corner. The peg would pivot about half of the left one before running into the brake pedal.
Hit a log hard enough and clang, clang, clang goes the brake lever
Still you'll have stronger pegs than stock, even if they don't pivot as far ...