The Zombies, in particular, gave a lot of new toys to other Zombie decks, with Hancock, Ghoulish MayorHancock, Ghoulish Mayor and Jason Bright, Glowing ProphetJason Bright, Glowing Prophet
Clone, Onslaught I just don't think most people realize how weird and awesome Clone was as a reprint in Onslaught
Even if your opponents are keeping you from accumulating experience counters, returning creatures (especially those with lower CMC) to your hand is still quite useful
One thing that makes encounters with wild Pokmon so interesting is the opportunity to catch and add them to your team
Sometimes players may have to cut some of their favorite cards in order to keep the total number down, so deciding which cards go best with each other is key
Similarly, permanents that phase out with counters phase in with those counters