Jumpluff

Jumpluff has pitiful stats for PvE, and is mostly a dex filler. Its double weakness to Ice-type attacks discourages its use for gym defense. The only niche that this cotton ball has going for it is in PvP, specifically Great League. 

Best PvE Offensive Moveset

• Bullet Seed gets STAB and allows Jumpluff to fulfill a Grass-type role.
• Infestation actually sports slightly superior stats, but lacks STAB and doesn't synergize well. 
• Fairy Wind is more beneficial for Fairy-type Pokemon. 
• Solar Beam offers the best offensive performance, dealing considerable damage. 
• Energy Ball deals more consistent damage as a 2-bar move, but falls behind overall due to how slow it is. 
• Acrobatics benefits from STAB, but lacks synergy with Jumpluff's fast moves.
• Aerial Ace is a step down and has the same problem. 
• Dazzling Gleam has no use. 

Best PvE Defensive Moveset

• Both Bullet Seed and Infestation perform almost identically on defense, the difference is miniscule. 
• Fairy Wind is one of the worst moves for defense, with its pitiful damage. 
• Aerial Ace can be used frequently as a 3-bar move, and benefits from STAB.
• Energy Ball being a Grass-type move can threaten certain Ice-type attackers that have a Water sub-typing. 
• Dazzling Gleam doesn't provide any meaningful coverage, but is faster than Energy Ball. 
• Acrobatics hits hard and fast, but takes a long time before it can be used, which is risky with Jumpluff's double weakness. 
• Solar Beam is too slow for defense. 

Fairy Wind is an interesting addition for Jumpluff; while it doesn't get STAB, the advantage of Fairy-typing helps in a handful of a matchups. Bullet Seed performs almost identically, but having STAB on a move that doesn't deal much damage isn't very significant. 

Energy Ball is recommended for its lesser energy cost than that of Solar Beam, which makes it less difficult to use when shields are up. Aerial Ace costs the least amount of energy, provides coverage against other Grass Pokemon, and can be used to bait shields. However, its STAB damage output isn't very impressive, and therefore the Community Day move Acrobatics can be chosen instead for much more threatening damage. The choice between the two is up to preference, as Jumpluff has very high bulk and can sometimes afford to take more damage while farming for the more energy-demanding move. Dazzling Gleam is the only coverage move available, and not only is it not very relevant for Jumpluff's defensive typing, but also costs a pricey 70 energy.