#003 Venusaur
Base Stats: 80 HP / 82 Atk / 83 Def / 100 SAtk / 100 SDef / 80 Spd
Ability: Overgrow (when HP drops below 33% grass-type attacks are boosted by 1.5x)
Projected Tier: Borderline
Notable Physical Movepool
Notable Special Movepool
Notable Support Movepool
Venusaur is a pretty damn nifty Pokemon and is the first on my list of projected OU / BL Pokemon. This effort by me is to try to change the pace of RMT threads around here, since all of them pretty much feature the same Pokemon within a small level of variation. You see lots of AGmences, CBtars, and SDchomps without a great deal of variety (but there are a few people with good variety on there teams, like Phuquoph). Anyways, onto the discussion.
Venusaur was known in advance for walling the fuck out of Raikou, even HP Ice Raikou, and could out-stall it and even phaze it with Roar to keep it from CMing up. Venusaur is hurt by how few PP Synthesis has in D/P, but it can still be a great disabling Pokemon and work as an excellent team supporter, opening up weaknesses and softening the opponent. Its typing makes it neutral to Earthquake, which is unfortunate, but part-poison also makes it neutral to Megahorn and resist Close Combat, making it possible to handle Heracross somewhat with a physical defense-oriented EV spread (it still absolutely hated Megahorn). Let's take a look at some possible Venusaur movesets.
Venusaur @ Choice Scarf
Nature: Timid (+Spd -Atk)
EVs: 196 HP / 204 Spd / 104 SDef
Trait: Overgrow
-Sleep Powder
-Leech Seed / Sleep Talk
-Earthquake
-Leaf Storm
Fast sleep status beaten only by CS Gengar in OU, as far as no setup time goes. Possible Pokes from UU that can beat it are CS Ninetales and CS Rapidash, but I don't expect them to be around much. You can lead with this, as the only attack that a double-status CS Gengar has that hits Venusaur for neutral is Shadow Ball. If you think it'll status you then you can opt for Sleep Talk instead of a fast Leech Seed so you can get a move off on it, although it resists Leaf Storm and is immune to Earthquake. But hey, you have a 33% chance of putting Gengar to sleep too. Anyways, this also outspeeds Raikou and can break its substitutes every time with Earthquake while taking Thunderbolts, HP Grasses, or HP Ices decently. Leaf Storm surprises CG Starmie and beats the heck out of them. This works best with Wish support.
Venusaur @ Poison Sludge
Nature: Timid (+Spd -Atk)
EVs: 116 HP / 192 Def / 200 Spd
Trait: Overgrow
-Sleep Powder
-Synthesis
-Sludge Bomb
-Grass Knot
Can sometimes survive an adamant Heracross CB Megahorn, but the best time to bring it in is on a baited / predicted Close Combat with Heracross. You outspeed it and can Sleep Powder it or whatever's switching in. Sludge Bomb is for Tangrowth mostly, whereas Grass Knot is for the myraid resistors of Sludge Bomb and for being a cool STAB against rock types since it's almost always 120BP against them.
Venusaur @ Poison Sludge
Nature: Sassy (+SDef -Spd)
EVs: 252 HP / 132 Def / 124 SDef
-Curse
-Earthquake
-Rock Smash / Leaf Storm
-Synthesis
Curse sets are on their way out (except for Cursetar), but this could be worth a shot. Each Curse boosts its attack by 100, making Earthquake hurt a fair amount. Rock Smash would be for Weavile, who is OHKOed at +2, and Leaf Storm does nice damage to Rhyperior even in a sandstorm. Synthesis over Rest since Rest is suicidal in what the metagame looks like.