Let's get straight to the list.
Pokémon (19)
4 Treeko (CLS 8/168)
4 Grovyle (Fairy Rise)
2 Sceptile (CLS 10/168)
2 Sceptile GX (Fairy Rise)
2 Eevee (SUM 101/149)
2 Leafeon GX (UPR 13/156)
2 Tapu Lele GX (GRI 60/145)
1 Deoxys (CLS 67/168)
Trainers (31)
4 Cynthia (UPR 119/156)
3 Guzma (BUS 115/147)
3 Pokémon Fan Club (UPR 133/156)
3 Lillie (UPR 125/156)
2 Judge (FLI 108/131)
1 Acerola (BUS 112/147)
3 Ultra Ball (SLG 68/73)
2 Net Ball (Fairy Rise)
3 Nest Ball (SUM 123/149)
2 Escape Board (UPR 122/156)
3 Choice Band (GRI 121/145)
2 Acro Bike (CLS 123/168)
1 Life Forest Prism Star (Fairy Rise)
Energy (10)
8 Basic Grass Energy
2 Double Colorless Energy (SLG 69/73)
So here's the deal. Turn 1 you have Eevee (or even if you don't you can use Nest/Ultra Ball) and you put it active (you want to go second with this deck) if you don't already have 1, Treeko from Net Ball is a possibility, and you have that on your bench. Lele for Fan Club and Fan Club for two more Treeko. Attach Grass to Eevee and evolve to Leafeon GX. Then Grand Bloom GX to evolve all your Treeko. Turn 2: Use Grovyle's ability to evolve all your Grovyle. SIMPLE! Seriously though, the 2-2 spread between the Celestial Storm and Fairy Rise Sceptile make sense because even using CLS Sceptile as an attacker is an option. Life Forest+Leafeon= a a Gold Potion+20 EVERY TURN. This makes Max Potion redundant. Deoxys is just for coverage, and I think it's a better fit than Latios. The supporter is a pretty standard (or what I think will be post rotation) and the only out of the ordinary item choice is Net Ball for Grass Pokemon/Energy and obviously Life Forest Prism Star as a Stadium for Grass Pokemon. 8 Basic Grass and 2 DCE seems a nice split, but I might cut a DCE for another Grass Energy as you only need DCE for Deoxys. I was also considering Counter Energy but it seems too situational for my liking with this deck. Like normal, tell me about my obvious mistakes and what I could improve with this list!
Pokémon (19)
4 Treeko (CLS 8/168)
4 Grovyle (Fairy Rise)
2 Sceptile (CLS 10/168)
2 Sceptile GX (Fairy Rise)
2 Eevee (SUM 101/149)
2 Leafeon GX (UPR 13/156)
2 Tapu Lele GX (GRI 60/145)
1 Deoxys (CLS 67/168)
Trainers (31)
4 Cynthia (UPR 119/156)
3 Guzma (BUS 115/147)
3 Pokémon Fan Club (UPR 133/156)
3 Lillie (UPR 125/156)
2 Judge (FLI 108/131)
1 Acerola (BUS 112/147)
3 Ultra Ball (SLG 68/73)
2 Net Ball (Fairy Rise)
3 Nest Ball (SUM 123/149)
2 Escape Board (UPR 122/156)
3 Choice Band (GRI 121/145)
2 Acro Bike (CLS 123/168)
1 Life Forest Prism Star (Fairy Rise)
Energy (10)
8 Basic Grass Energy
2 Double Colorless Energy (SLG 69/73)
So here's the deal. Turn 1 you have Eevee (or even if you don't you can use Nest/Ultra Ball) and you put it active (you want to go second with this deck) if you don't already have 1, Treeko from Net Ball is a possibility, and you have that on your bench. Lele for Fan Club and Fan Club for two more Treeko. Attach Grass to Eevee and evolve to Leafeon GX. Then Grand Bloom GX to evolve all your Treeko. Turn 2: Use Grovyle's ability to evolve all your Grovyle. SIMPLE! Seriously though, the 2-2 spread between the Celestial Storm and Fairy Rise Sceptile make sense because even using CLS Sceptile as an attacker is an option. Life Forest+Leafeon= a a Gold Potion+20 EVERY TURN. This makes Max Potion redundant. Deoxys is just for coverage, and I think it's a better fit than Latios. The supporter is a pretty standard (or what I think will be post rotation) and the only out of the ordinary item choice is Net Ball for Grass Pokemon/Energy and obviously Life Forest Prism Star as a Stadium for Grass Pokemon. 8 Basic Grass and 2 DCE seems a nice split, but I might cut a DCE for another Grass Energy as you only need DCE for Deoxys. I was also considering Counter Energy but it seems too situational for my liking with this deck. Like normal, tell me about my obvious mistakes and what I could improve with this list!