Here are some facts that everyone should know, but for the ones who don't:
-Marth's neutral-B(Shieldbreaker), when used to it's max extent, is great for recovering when you get knocked to the side pretty high. Unless you're at places like Temple.
-Pit, Charizard, and Metaknight all have the ability to fly/glide by holding down the jump button while airbourne, but Metaknight's is the only one that isn't considered as an up-B
-Right after a running kick attack, or dash-A, with Falco connects, you can immediately use an up-smash by tilting up on the C-Stick
-Luigi's Down-B midair is an excellent aerial recory that's not considered Up-B, you just have to press B fast enough
-Around 65-80%, Luigi's Up-B will KO if it connects on the ground
-The characters who can jump multiple times are considered "good recoverers", but in metal mode, they are basically the worst.
-You can use any Up-B more than once if you get hit after you use it the first time, but R.O.B. can use Up-B multiple times before it runs out of fuel.
-Bowser(Side-B and tilt control stick torwards the edge.), Ganondorf(Side-B while neither Ganondorf or victim is onstage), DK(F-Grab, walk off), Kirby(Suck In, walk off), and DeDeDe(Suck in, walk off) have suicidal moves. While Wario(Bite) and Ike(Aether) CAN have suicidal moves.
-Moves decrease to 0 damage if you use them too much(AKA spam)
-You do not, despite popular belief, get any special bonuses for completing Boss Battles/All Star without using any heart containers.
There are many more, but I'll stop here.