Double rolls and double airdodges.

[Rango the Mercenary]

Notice how certain characters seem to be immune to punishes while rolling and dodging? While it may not be a literal "double roll", they're able to quickly jump into another roll right as the first one ends. These are the ones you need to watch out for while trying to punish them.

I don't have a list of characters because it's something I only recently started looking into. But compared to some characters, like Luigi, Bowser, and Ike, certain characters like Wii Fit Trainer and Sheik seem to buzz right by you, then punish you from behind for trying to beat their first roll.

Do you know the rest of characters who seem to make their dodges instantly?

 

[MezzoMe]

I haven't found any, actually, every roll has 10 frames endlag (the wavedash landlag, if you need a reference) and 4 frames start-up, in other words, they are vulnerable for 14 frames between a roll and another, are you sure that you aren't hitting the opponent too early or too late?

 

[dragontamer]

Some characters roll faster than others. But they all seem to have huge points of vulnerability at the end of the roll.

 

[Flawed]

Adult Links Back roll? Rosalina's rolls? Toonlinks forward and instant back roll? Luigi's super fast double or triple airdodges?

 

[Darklink401]

Little Mac's roll is super quick.

That's all I know XP