Let's see...Let's see if I can't come up with anything...
-Snake's Utilt:
If both Dedede and Snake are on the ground (tested on SV) Utilt doesn't kill until he's past 144%, the best DI for it is holding towards him and then you of course momentum cancel
-Yoshi Ledge camping
If Yoshi starts to camp on the edge with eggs, and you are in the middle/towards that edge, space yourself so that the head of D3's hammer from ftilt will be right above the edge. This will break the egg and stop you from taking damage.
-Edge tricksies
When someone's recovering and you don't feel brave enough to go off stage (sissy), there are a few things that are fairly safe. If someone is coming up from beneath the stage/drop off the edge, Dsmash can stage spike. Space so the hammer head will spin over it while you're facing the edge. Another option is, with your back facing the edge, to do a jump once they get on the edge. If they jump up, position yourself and bair them; if they get up regularly, fast fall bair or turn around and Inhale; if they getup attack, the options are the same, but Inhale with armor is safer. If they get up roll, Inhale, turn around and spit them off stage again.
-Platforms and grabs
If, for example, you are on Battlefield's right platform and grab someone on it while facing left (towards the center of the stage) running off and regrabbing, while not guaranteed, works decently. This is best done if you drop through the platform/run off and shield in front to do a shield grab
-Double Down Tilt
A very silly technique in which you do two Dtilts in a row while someone's recovering onto the stage/grabs the ledge/shields one Dtilt. Hardly practical, but manages to work every now and then
-Platform Pressure
If someone is on a platform above you and not in killing percent (aka, utilt won't kill them) Something I like to do is, utilizing several jumps, assault with bairs until either A) they get hit, or B) I end with turnaround Inhale
-Bair and tripping
In conjunction with the above (and just in general) Bair can trip at low percentages, and should always be followed up with something, i.e. another bair or a grab
-Waddle Doos
If a waddle doo is nearby and charging its laser and some poor soul is in your grip, simply hold them in your hands while they get whipped, they'll be released right in front of you, ready to be grabbed once again
Just stuff I thought of from my game I'd like to share.