Naming conventions:
351Castform-Sunny.png or 412Burmy-Sandy.png for full-size or thumbnails
351MS-Sunny.png or 412MS-Sandy.png for sprites, when available
Then in the pokedex file, each pokemon would have a property called forms like so (example is for pikachu):
All forms I could find are below:
Pikachu Cosplay Pikachu
Pikachu Pikachu Rock Star
Pikachu Pikachu Belle
Pikachu Pikachu Pop Star
Pikachu Pikachu, Ph. D
Pikachu Pikachu Libre
Pichu Spiky-eared Pichu
Unown One form
Castform Normal
Castform Sunny Form
Castform Rainy Form
Castform Snowy Form
Deoxys Normal Forme
Deoxys Attack Forme
Deoxys Defense Forme
Deoxys Speed Forme
Burmy Plant Cloak
Burmy Sandy Cloak
Burmy Trash Cloak
Wormadam Plant Cloak
Wormadam Sandy Cloak
Wormadam Trash Cloak
Cherrim Overcast Form
Cherrim Sunshine Form
Shellos West Sea
Shellos East Sea
Gastrodon West Sea
Gastrodon East Sea
Rotom Rotom
Rotom Heat Rotom
Rotom Wash Rotom
Rotom Frost Rotom
Rotom Fan Rotom
Rotom Mow Rotom
Giratina Altered Forme
Giratina Origin Forme
Shaymin Land Forme
Shaymin Sky Forme
Arceus Arceus
Basculin Red-Striped Form
Basculin Blue-Striped Form
Darmanitan Standard Mode
Darmanitan Zen Mode
Deerling Spring Form
Deerling Summer Form
Deerling Autumn Form
Deerling Winter Form
Sawsbuck Spring Form
Sawsbuck Summer Form
Sawsbuck Autumn Form
Sawsbuck Winter Form
Tornadus Incarnate Forme
Tornadus Therian Forme
Thundurus Incarnate Forme
Thundurus Therian Forme
Landorus Incarnate Forme
Landorus Therian Forme
Kyurem Kyurem
Kyurem White Kyurem
Kyurem Black Kyurem
Keldeo Ordinary Form
Keldeo Resolute Form
Meloetta Aria Forme
Meloetta Pirouette Forme
Genesect Genesect
Vivillon Icy Snow Pattern
Vivillon Polar Pattern
Vivillon Tundra Pattern
Vivillon Continental Pattern
Vivillon Garden Pattern
Vivillon Elegant Pattern
Vivillon Meadow Pattern
Vivillon Modern Pattern
Vivillon Marine Pattern
Vivillon Archipelago Pattern
Vivillon High Plains Pattern
Vivillon Sandstorm Pattern
Vivillon River Pattern
Vivillon Monsoon Pattern
Vivillon Savanna Pattern
Vivillon Sun Pattern
Vivillon Ocean Pattern
Vivillon Jungle Pattern
Vivillon Fancy Pattern
Vivillon Poké Ball Pattern
Flabébé Red Flower
Flabébé Yellow Flower
Flabébé Orange Flower
Flabébé Blue Flower
Flabébé White Flower
Floette Red Flower
Floette Yellow Flower
Floette Orange Flower
Floette Blue Flower
Floette White Flower
Floette Eternal Flower
Florges Red Flower
Florges Yellow Flower
Florges Orange Flower
Florges Blue Flower
Florges White Flower
Furfrou Natural Form
Furfrou Heart Trim
Furfrou Star Trim
Furfrou Diamond Trim
Furfrou Debutante Trim
Furfrou Matron Trim
Furfrou Dandy Trim
Furfrou La Reine Trim
Furfrou Kabuki Trim
Furfrou Pharaoh Trim
Aegislash Shield Forme
Aegislash Blade Forme
Pumpkaboo Average Size
Pumpkaboo Small Size
Pumpkaboo Large Size
Pumpkaboo Super Size
Gourgeist Average Size
Gourgeist Small Size
Gourgeist Large Size
Gourgeist Super Size
Xerneas Neutral Mode
Xerneas Active Mode
Zygarde Zygarde Cell
Zygarde Zygarde Core
Zygarde Zygarde 10% Forme
Zygarde Zygarde 50% Forme
Zygarde Zygarde Complete Forme
Hoopa Hoopa Confined
Hoopa Hoopa Unbound
Naming conventions:
351Castform-Sunny.png
or412Burmy-Sandy.png
for full-size or thumbnails351MS-Sunny.png
or412MS-Sandy.png
for sprites, when available Then in the pokedex file, each pokemon would have a property calledforms
like so (example is for pikachu):All forms I could find are below: Pikachu Cosplay Pikachu Pikachu Pikachu Rock Star Pikachu Pikachu Belle Pikachu Pikachu Pop Star Pikachu Pikachu, Ph. D Pikachu Pikachu Libre Pichu Spiky-eared Pichu Unown One form Castform Normal Castform Sunny Form Castform Rainy Form Castform Snowy Form Deoxys Normal Forme Deoxys Attack Forme Deoxys Defense Forme Deoxys Speed Forme Burmy Plant Cloak Burmy Sandy Cloak Burmy Trash Cloak Wormadam Plant Cloak Wormadam Sandy Cloak Wormadam Trash Cloak Cherrim Overcast Form Cherrim Sunshine Form Shellos West Sea Shellos East Sea Gastrodon West Sea Gastrodon East Sea Rotom Rotom Rotom Heat Rotom Rotom Wash Rotom Rotom Frost Rotom Rotom Fan Rotom Rotom Mow Rotom Giratina Altered Forme Giratina Origin Forme Shaymin Land Forme Shaymin Sky Forme Arceus Arceus Basculin Red-Striped Form Basculin Blue-Striped Form Darmanitan Standard Mode Darmanitan Zen Mode Deerling Spring Form Deerling Summer Form Deerling Autumn Form Deerling Winter Form Sawsbuck Spring Form Sawsbuck Summer Form Sawsbuck Autumn Form Sawsbuck Winter Form Tornadus Incarnate Forme Tornadus Therian Forme Thundurus Incarnate Forme Thundurus Therian Forme Landorus Incarnate Forme Landorus Therian Forme Kyurem Kyurem Kyurem White Kyurem Kyurem Black Kyurem Keldeo Ordinary Form Keldeo Resolute Form Meloetta Aria Forme Meloetta Pirouette Forme Genesect Genesect Vivillon Icy Snow Pattern Vivillon Polar Pattern Vivillon Tundra Pattern Vivillon Continental Pattern Vivillon Garden Pattern Vivillon Elegant Pattern Vivillon Meadow Pattern Vivillon Modern Pattern Vivillon Marine Pattern Vivillon Archipelago Pattern Vivillon High Plains Pattern Vivillon Sandstorm Pattern Vivillon River Pattern Vivillon Monsoon Pattern Vivillon Savanna Pattern Vivillon Sun Pattern Vivillon Ocean Pattern Vivillon Jungle Pattern Vivillon Fancy Pattern Vivillon Poké Ball Pattern Flabébé Red Flower Flabébé Yellow Flower Flabébé Orange Flower Flabébé Blue Flower Flabébé White Flower Floette Red Flower Floette Yellow Flower Floette Orange Flower Floette Blue Flower Floette White Flower Floette Eternal Flower Florges Red Flower Florges Yellow Flower Florges Orange Flower Florges Blue Flower Florges White Flower Furfrou Natural Form Furfrou Heart Trim Furfrou Star Trim Furfrou Diamond Trim Furfrou Debutante Trim Furfrou Matron Trim Furfrou Dandy Trim Furfrou La Reine Trim Furfrou Kabuki Trim Furfrou Pharaoh Trim Aegislash Shield Forme Aegislash Blade Forme Pumpkaboo Average Size Pumpkaboo Small Size Pumpkaboo Large Size Pumpkaboo Super Size Gourgeist Average Size Gourgeist Small Size Gourgeist Large Size Gourgeist Super Size Xerneas Neutral Mode Xerneas Active Mode Zygarde Zygarde Cell Zygarde Zygarde Core Zygarde Zygarde 10% Forme Zygarde Zygarde 50% Forme Zygarde Zygarde Complete Forme Hoopa Hoopa Confined Hoopa Hoopa Unbound