As seen in https://minecraft.curseforge.com/projects/auxiliary-biomes/images most of the remaining biomes are rather bad, perhaps they can be revamped and included.

• Marsh: Currently not realistic at all. Make it look closer to this
• Forested Island: Could be reintroduced as a Deep Ocean variant.
• Ice Wasteland: Not sure. Could be an ice plains / glacier variant.
• White Forest: Not sure. Seems pretty boring.
• Wasteland: Could be reintroduced as a biome within the deep desert, a dried lakebed. Maybe even below sea level. Certainly needs to be smaller or at least more appealing, and certainly not anywhere near normal biomes.

Forest Island is now a Traverse biome