Yea Raysdoc play him or Dragoomba's R.O.B. Both are pretty good if you want R.O.B tips/training from them. Oh and PT tips...
Squirtle
Jab Cancel, Dthrow (always effective)
Jab Cancel, Dtilt, Fair (It works at lower damages but you may get in another Fair at very low percentages)
Shell Shifting, Sliding Usmash (This is a hard technique to pull off and explain but offers some incredible mindgames when mastered)
Shell Shifting (Incredible technique to use and can be used to create incredible mindgames, using this into Grab, an aerial attack are all fine and dandy but the best use of it to my knowledge is in a Sliding Usmash)
Ivysaur
SH to Bair, Ftilt (Works a good number of the time and a great combo to use)
SH to Nair, Bullet Seed (Make sure you do you get the spike at the end of the Nair and go straight into a Bullet Seed as soon as you hit the ground)
[Vine Whipping] SH to Bair, Jump to Double Bair (It's a great spacing technique which is necessary for using Ivysaur, it works best at lower damages)
Standard Combo, turn around, grab (When you get your opponent caught in the continuous standard combo they may try to roll behind you, this is your chance to grab them and deal with them accordingly)
Charizard
Chain grab (I've found Charizard's Chain grab pretty effective but not the best, it works best on mid to heavyweight fighters, probably not even worth mentioning)
Jab Cancel, Grab (Pretty effective but stops working for most characters between 40% - 50%)
[Corner opponent close to the edge of stage] Jab Cancel, Fthrow, SH to Nair (You do the same as the first combo but you Fthrow your opponent, your opponent should be off the stage, now if you time yourself perfectly when you Short Hop you could possibly get your enemy in a position where they can stage spiked with the Nair but most likely will fail it may work but most likely won't. This combo works a good number of the time whether just build up damage on the stage or to stage spike them)
For ROB, abuse FAir and F-tilt, and don't be afraid to use BAir. For PT, you're pretty much on your own. PT has every single playstyle combined, literally.