Really you're not giving us much to work with. I could build a team for you but then it wouldn't really be your team.
Set dump:
Venusaur @ Leftovers
Calm
252 HP, 252 Sp. Def, 4 Sp. Atk
-Energy Ball
-Synthesis
-Sleep Powder
-Sludge Bomb
Umbreon @ Leftovers
Impish
252 Defence, 252 HP, 4 Attack
-Payback
-Toxic
-Moonlight
-Substitute
Starmie @ Choice Specs / Choice Scarf
Timid
252 Speed, 252 Sp. Atk, 4 HP
-Surf
-Thunderbolt
-Ice Beam
-Psyshock
Salamence @ Choice Band / Choice Scarf
Naive
252 Speed, 252 Attack, 4 Sp. Atk
-Dragon Claw
-Earthquake
-Fire Blast
-Crunch