Massive
Smash Champion
It depends on what you mean by edge guard, I guess.
If you're talking about ledgehogging, I think Fox is probably the best at it. He can firefox stall or pop off and regrab within invincibility frames. He's very hard to get off the ledge once hes on, and you can't do a huge amount about it.
If you're talking about chasing people off the stage to prevent them from getting back to the edge, Jigglypuff is by a large margin the best. Jigglypuff's abilities are not substantially diminished by being off-stage, and really the entire level is jigglypuff's stage. Puff can chase opponents anywhere off screen and easily recover with no issue, there's no contest on this one.
If you're talking about holding the ledge and punishing people trying to get back onto the stage, Sheik is arguably the best. Drop > Jump > bair is impossibly good at repelling recoveries, and is many times more than enough to take the stock. Sheik also falls slowly enough that you can easily regrab the ledge in many instances, making this tactic incredibly safe and effective.
If you're talking about remaining on the stage and keeping people off the ledge, Marth is insanely good at it. He can parry or jab for spacies, dtilt everyone else, and fsmash for higher than normal recoveries. His dair can end a stock without even leaving the stage.
There's not really a clear winner of all of these in my eyes, although there is a lot of crossover in these abilities, which is a large part of why fox and sheik are so good. I consider Falco to be "pretty good" at all of these, just not the best. This is arguably a large part of why he's so good in general.
If you're talking about ledgehogging, I think Fox is probably the best at it. He can firefox stall or pop off and regrab within invincibility frames. He's very hard to get off the ledge once hes on, and you can't do a huge amount about it.
If you're talking about chasing people off the stage to prevent them from getting back to the edge, Jigglypuff is by a large margin the best. Jigglypuff's abilities are not substantially diminished by being off-stage, and really the entire level is jigglypuff's stage. Puff can chase opponents anywhere off screen and easily recover with no issue, there's no contest on this one.
If you're talking about holding the ledge and punishing people trying to get back onto the stage, Sheik is arguably the best. Drop > Jump > bair is impossibly good at repelling recoveries, and is many times more than enough to take the stock. Sheik also falls slowly enough that you can easily regrab the ledge in many instances, making this tactic incredibly safe and effective.
If you're talking about remaining on the stage and keeping people off the ledge, Marth is insanely good at it. He can parry or jab for spacies, dtilt everyone else, and fsmash for higher than normal recoveries. His dair can end a stock without even leaving the stage.
There's not really a clear winner of all of these in my eyes, although there is a lot of crossover in these abilities, which is a large part of why fox and sheik are so good. I consider Falco to be "pretty good" at all of these, just not the best. This is arguably a large part of why he's so good in general.