I've gotten alot of starters, from all generations, as well as some X/Y only (uncommon, mostly) Pokémons to my Omega Ruby. I try to only trade decent pokemons, and by decent I mean either rare or strong, unless I get a crap zigzagoon or anything like that, I trade those back right away. It's a really good way of completing the pokedex, although it's really really slow.