Well, this is really early to make one of these, especially because all the good breeding "material" is yet to be reached. Nonetheless, here we go:
Get a Buneary/Sentret to breed Baton Pass onto Blaziken. The Speed boosts will come in handy for your team.
When you get to Tanzan Cove, get a Poliwag to get Belly Drum onto Azumarill. Belly Drum + Aqua Jet is the standard Azumarill set for a reason.
Get Body Slam from Purugly/Pancham/Torkoal. That 30% chance is pretty neat, especially because Ice Shard, Icicle Crash and EQ are pretty much the only viable moves we can get for it.
Electro Ball is terrible on Magnezone, as it scales with Speed. You should also definitely get a Steel STAB move.
In the Wasteland is an event for a Spiritomb. That thing can breed both Memento and Nasty Plot onto Cofagrigus. Quite a bit later, you also get a Trick Room TM, great for your not-so-fast team. A Cofagrigus Nasty Plot, Shadow Ball, HIdden Power and Trick Room (or Trick Room on someone else) is amazing.
Only 3 gyms don't have a line-up with good speed, so Trick Room will really come in handy.
Night Slash and a Scope Lens (O.Dept Store) give you a 50% chance to crit. 100% if you have the ability Super Luck. If you do Baton Pass Speed or use Trick Room, Moxie is better.