Back when the games came out, I usually WT just trade evolution or rare encounter pokemon. Now, I exclusively WT breeding rejects only, that usually have 3-5 IVs. Some of the Pokemon I released onto WT were Joltik, Togepi, Treecko, Dratini, Mudkip, etc.
In return, I get a lot of breeding rejects of Pokemon I don't have, which is actually great for me. But I do occasionally get the common Route 1 Pokemon.