Alright, let's look at those Goomy!

Moveset A: Curse, Dragon Breath, Dragon Pulse, Iron Tail, Poison Tail, Return, Round
Moveset B: Attract, Curse, Double Team, Dragon Breath, Iron Tail, Poison Tail, Protect, Rain Dance, Return, Round, Snore, Tackle, Toxic, Water Gun, Water Pulse
Moveset C: Attract, Curse, Infestation, Iron Tail, Poison Tail, Return, Round, Sludge Bomb, Sludge Wave, Snore, Swagger
Moveset D: Body Slam, Curse, Dragon Breath,Dragon Pulse, Iron Tail, Outrage, Poison Tail, Return, Rock Slide, Round, Tackle, Toxic
Moveset E: Confide, Curse, Double Team, Iron Tail, Poison Tail, Rain Dance, Return, Round, Swagger, Tackle
Moveset F: Curse, Double Team, Dragon Pulse, Iron Tail, Outrage, Poison Tail, Protect, Rain Dance, Rest, Return, Round, Sleep Talk, Substitute, Sunny Day, Swagger, Toxic
Moveset G: Bide, Curse, Double Team, Iron Tail, Poison Tail, Return, Rock Slide, Round, Tackle, Toxic
Moveset H: Bide, Curse, Dragon Breath, Iron Tail, Outrage, Poison Tail, Protect, Return, Round, Tackle

Personal rec: I'd recommend B or F, with potentially D as a third option. A and H offer nothing other movesets can't do better.