Dair and Down B are good aggressive options, double jump can retreat to ledge.
Down B snaps to ledge instantly, though mess it up and you lose a whole stock.
Also, if you really wanna get crazy, fall into the opponent but double jump out before you're in trouble. Then you can see how they anticipate your landing, and you can keep that in mind the next time you land. (Example: I'm Yoshi and I fall towards Marth, looking like I'm about to land, but I double jump as he dashes back and pivot grabs. Now I know I should fastfall into a spotdodge or something next time I land)