I posted some >B strats in the 101 thread while back, but here they are again:
Foxtrot away, >B towards is a nice tool for spacing. It's great against sex kicks and other poor range aerials.
What exactly do you mean by dash pivot forward B? Is that dash, then tap the other way for a slide animation, then cancel out of it with forward B? If so, that would be uneccesary, as dash can cancel immediately into >B. Which is fairly useful btw.
If you shorthop and >B, it cancels all vertical momentum and slows down horizontal momentum considerably. You can use this by dashing at the opponent then shorthop and >B. The pullback and momentum change can cause the opponent to whiff and eat the >B. Also a useful mixup with dash attack. Additionally it goes over low tilts like Ness/Lucas/Sonic.
>B also ***** shields pretty hard. If you can see the opponent's shield is wisibly worn down, try and get them to shield a >B and it may break a shield. Also, blocked >B, then chase into blocked punch usually breaks a shield.