I guess my "Main team" is currently my eeveelutions run. It's the only save file I used to go through E16 content, both of my other characters are still babysitting seducing Ciel.
The top squad is:
2 Vaporeons (Scylla & Triton) - one EV trained in HP + SpA, the other in HP + Def. These two are insanely good for doubles with their Surf + Water Absorb combo. Poor Charlotte.
Espeon (Despair) - with best IVs out of all of my pokemon, my ace - after E16 she finally has some decent TM moves
Sylveon (Brandish) - Light Screen, Pixilate + 1 PP Trump Card to OHKO bosses like Dittoceus or Solochomp
Flareon (Infernus) - Flame Charge / Fire Blitz + Guts + Charcoal (sometimes I have him poisoned before the battle and have someone else setup Sunny Day - Fire Blitz with all the buffs from Guts, Charcoal and Sunny Day + top EVs and IVs in attack hits VERY hard)
Glaceon (Borealis) - nothing too awesome here but ice type is always nice to have
I have 2 decently trained Jolteons, an Umbreon, a Leafeon and a second Sylveon. I usually switch one or two of my primary members with some of these against bosses as needed. Poor Leafeon almost never leaves PC.