Here are skills would characters the best can have Goku: king kai fist 20x super saiyan(1 2 and 3)warp kamehameha super spirit bomb Kamehameha(or only potara) Picollo:destructive wave, sync with nail, fuse with kami, light grenade, hellzone grenade, special beam cannon Gohan(adult):kamehameha, jackhammer, super kamehameha, super saiyan, super saiyan 2, elder kai's unlock ability Vegeta:galick cannon, final flash, meteor flash, meteor break, super saiyan, Super saiyan 2 Great saiyaman:justice punch, justice kick, justice carnaval, justice flash
Super Buu is the best buu if you unlock absorption to get absorption you need 10000 kili and then you unlock it what it does is, is when you use the move super buu picks a random person and absorbs them and takes on two of there moves so if he happens to absorb gotenks he gets victory cannon and super ghost kamiakaze attack, another example is vegeta lets you use galick gun and final flash, cell is energy field and spirit bomb those are the only characters I have seen him absorb so far
When the match start dash to the person you are fighting and hit the punch button To knock them on the ground then when they get up start to punch and keep punching until their energy on orange then use kamahamahamaha or a move lke To finish them off
The best character (in my view) is a customised Vegeta to look like this:- Super Saiyan, Super Saiyan Two, Galick Gun, Big Bang Attack, Big Bang Attack, Angel's Halo, Meditation. Fully powered up this Vegeta's Big Bang Attack can cause nearly two bars or seventeen hundred attack points when successful. With the Halo he won't loose Ki from powering up and the Meditation means he only uses have his Ki per attack so he remains really powered up throughout a fight and opponents will be left on th flat of their backs.