This is a pure Rain Dance team. I have looked at a few others but I don't really like them, so this is mine:

Omastar, Modest @Leftovers (w/ Swift Swim)
52 HP, 52 Def, 152 Sp Atk, 252 Spd
-Surf
-Ancientpower
-Earth Power
-Ice Beam/Rock Polish

Kingdra, Modest @Damp Rock (w/ Swift Swim)
112 Def, 252 Sp Atk, 112 Sp Def, 32 Spd
-Ice Beam
-Surf
-Dragonbreath
-Rain Dance

Relicanth, Adamant @Rindo Berry (w/ Swift Swim)
252 Atk, 6 Sp Def, 252 Spd
-Earthquake
-Rock Slide
-Bounce
-Waterfall

Zapdos, Naive @Wise Glasses
6 HP, 252 Sp Atk, 252 Spd
-Rain Dance
-Air Cutter
-Thunder
-Swift/Signal Beam

Raichu, Naive @Light Ball
6 HP, 252 Sp Atk, 252 Spd
-Surf
-Thunder
-Grass Knot
-Thunder Wave/Rain Dance

Kabutops, Adamant @Muscle Band (w/ Swift Swim)
6 HP, 252 Atk, 252 Spd
-Rock Slide
-X-Scissor
-Waterfall
-Body Slam

Please tell me what you think!

This belongs in the team rating section

since both raichu and zapdos are mono special attackers timid is a better nature
Light ball only works for pikachu
plus your team is basically all sweepers bar kingdra
Omastar consider Icy wind if your worried about speed, Hits for ice damage plus it slows down the opponent.
also having 3 pokémon that have a 4x weakness to grass isn't a good Idea

You could add an annoyer with Ludicolo. I used to have one of those and they are extremely difficult to uproot once they get setup. Im pretty sure this was what it was,

@ Leftovers
Rain Dish - Calm

~ Toxic
~ Rain Dance
~ Substitute
~ Leech Seed

or if you want to go with a more aggressive pokemon psypoke moveset is good too,

@ Leftovers
Swift Swim - Modest

~ Ice Beam
~ Surf
~ Rain Dance
~ Energy Ball

Ludicolo doesn't make for the best sweeper but then again it is what it is. I have the feeling we are all going to get slapped for doing this outside of the rating center anyways haha... but seriously you need to do this in the rating center. And I was reading they have a rule where you need to have 25 posts before you can even make a request for a review...