So here is my team so far on my black 2 game, I would like ratings and some advice and any ideas for my 6th member.
Serperior (Starter)
-Serious Nature
-Leech Seed
-Aqua Tail
-Leaf Blade

Ability:Water Absorb
-Naughty Nature
-Acid Armor
-Ice beam

Ability:Battle Armor
-Adamant Nature
-Cross Poison
-Toxic Spikes

-Modest Nature
-Magnet Rise
-Charge Beam
-Flash Cannon

Ability: Defiant
-Sharp Beak
-Careful Nature
-Crush Claw
-Aerial Ace

I'm one who pays attention to natures and tries to get good ones, but my early pokemon (Serperior and Vaporeon) Didn't get good natures because I wasn't sure which one would be the most beneficial (Serperior) or the pokemon was rare and I just got the first one i saw (vaporeon). All the others were actually coincidental.
Now about my 6th member, I need coverage from grass and electric types. I was thinking of something that can easily hit both, maybe a dragon type but I would like to hear suggestions from you all that read this. So thanks in advance.