Sandy

Spawning data tags simply contain a list of Biomes. If you're referring to this list for a Pokemon, please double-check if it has an Anti Condition or Anti Biome. Anti Conditions and Anti Biomes are a way to essentially state: not in this biome/condition, so you'll need to cross-reference them. For instance, if a Pokemon is set to spawn in is_ocean, but has an anti condition of is_cold, it will not spawn in cold oceans.

Our Pokemon spawns are generally based on default Cobblemon configurations with additions to allow the entire dex to spawn in all Minecraft biomes and supported biome mods. Most biome mods are supported such as Terralith, Oh Biomes You'll Go, Incendium, Better Nether, Gardens of the Dead, and The Bumblezone. Other biome mods may also be compatible, provided they label their biomes with data tags.

Sandy Biomes
minecraft:badlands	minecraft:eroded_badlands	minecraft:wooded_badlands
minecraft:desert	terralith:ashen_savanna	terralith:red_oasis
terralith:warped_mesa	terralith:white_mesa	terralith:ancient_sands
terralith:desert_canyon	terralith:cave/desert_caves	terralith:desert_oasis
terralith:desert_spires	terralith:lush_desert	terralith:sandstone_valley
byg:atacama_desert	byg:mojave_desert	byg:windswept_desert
wythers:danakil_desert	wythers:is_desert	wythers:badlands_desert
wythers:desert_island	wythers:kwongan_heath	wythers:outback_desert
wythers:red_desert	wythers:sandy_jungle