Lotad

Stats
Swift Swim: Doubles speed in the rain. HP:
40
Rain Dish: Restores 1/16 HP every turn in the rain. Atk:
30
Def:
30
SpA:
40
SpD:
50
Spe:
30

Offensive Rain

Ability: Swift Swim Lotad is the fastest thing around in the rain, and can hit very hard against the majority of the tier with Surf. Energy Ball takes out the fish and absolutely annihilates Wooper. Ice Beam hits harder against the likes of Sunkern and Seedot, while HP Flying allows you to hit other Lotads as well at the cost of a power drop on the other two. If you do run HP Flying, use 30 IV in every stat except speed to avoid losing to other Lotad.
Item: Life Orb
Nature: Modest
EVs: 4 HP, 252 SpA, 252 Spe
Moves: - Surf
- Energy Ball
- Ice Beam / HP Flying
- Rain Dance

SubSeed

Ability: Rain Dish As with every Grass-type, SubSeeding is a viable option on Lotad. With rain support though, Lotad gets a Rain Dish boost which makes him significantly better equipped to restore HP than his fellow Grass-types. HP Flying hits hard against all of the Grass types while also providing generally good coverage. The final slot can go to Protect to help you stall better, Toxic to improve the damage from Leech Seed, or Rain Dance to prolong your Rain Dish boost.
Item: Leftovers / Damp Rock
Nature: Calm
EVs: 252 HP, 4 Def, 252 SpD
Moves: - Substitute
- Leech Seed
- HP Flying
- Protect / Toxic / Rain Dance

Swords Dance

Ability: Swift Swim Lotad can Swords Dance up to become an unexpected physical attacker, though not a very good one. It's only the surprise element that allows this set to work at all. Return is your main form of damage, while Seed Bomb hits anything that doesn't resist it. It also destroys Wooper with no boost. Zen Headbutt is pretty much your only other physical option, and hits harder against Kakuna and Weedle, while Synthesis will restore your health. However, Lotad always appreciates rain support, and Synthesis will be crippled in rain. Warning: Return cannont 2HKO Metapod even after a Swords Dance. Make sure that the foe's physical walls are weakened before attempting a sweep.
Item: Life Orb
Nature: Adamant
EVs: 4 HP, 252 Atk, 252 Spe
Moves: - Swords Dance
- Return
- Seed Bomb
- Synthesis / Zen Headbutt

Other Options:

EVs:

Counters: