4 Radiant Charizard $33.46 It's inevitable, right
(Choose any number of permanents and/or players, then give each another counter of each kind already there.) Equip Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate
Sometimes, all you really want is to toss a whole bunch of cards straight from your opponents hand into the discard pile
Varchild, Betrayer of Kjeldor could be fun in some sort of group slug deck where you give your opponent tokens but in a harmful manner (maybe with something like Trespasser's Curse on the battlefield), although she might be better in the 99, since mono-red is pretty limiting
Having it ready to go can be a good "rattlesnake" tactic, too, encouraging opponents to attack somewhere else
Lair of the Hydra from Adventures in the Forgotten Realms can become a hydra itself, so it almost counts as two cards