Example of biome blending on trees using a "WorldEdit" brush
Brush with World Edit ! '/br biome sphere 5 Red' Exemple water color gradiant
"Red" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Red
"Orange" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Orange
"Yellow" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Yellow
"Green" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Green
"Cyan" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Cyan
"Blue" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Blue
"Purple" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Purple
"Pink" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Pink
"Magenta" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Magenta
"White" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full White
"Black" Biome Color: Grass / Foliage / Water + Waterfog Normal plain color Sky + fog
Full Black

This datapack adds a collection of colorful biomes, for creative worlds or builders! It's also compatible with world Edit and applicable with the /fillbiome vanilla command