A lot of characters are good...
Meta Knight, Kirby, DeDeDe and ROB: Amazing recovery with great aerials. You're dead.
Mario: Lots of edgeguarding tools are in his disposal. A master of cape and FLUDD will edgeguard your butt.
Ness and Lucas: PK is nice (especially when tail whipped), but there's also PK Freeze, PK Flash, and Ness's PK Fire-to-meteor that we can't forget.
Marth and G&W: Floaty. Aerials have good range. Can cause problems.
Snake: Mentioned previously. Give him some time, half of the stage becomes against you.
Falco: Pew pew pew! And a spike.
Pit: 3 extra jumps, strong aerials, a shield (that acts like Mario's cape when "sweet spotted"), arrows that can be aimed and wings to make it back.
Peach: Can float, throw turnips (believe me, that helps), and her F-air is a killer. Can use Toad to counter those who attack her, since his barf has more knockback this time.
That's all I can think of right now.
Basically, a lot of characters are good at edgeguarding. You just have to be good at it.