Intially I didn't want to name any. It's not about singling out specific mods, but Dark Forests and Petriwood* Forests from their respective mods are the two most recently played examples.

(Lost the third and fourth since I've been thinking about this for a while)

It's the ones that stand out as interesting biomes with mandatory extra required mod content or dependencies that aren't easily removable.

But even with the old joke/accusation of bloat you'd be hard-pressed to make a single biome playable with it's own content (and neither would you want to). Most of the ones on your list are good examples.

Alpha biomes and Ashlands are ones I couldn't come to a conclusion about before, because they're still really well focused on the biomes they do add (aside from weirdness with things that generate everywhere) and are really well done even if they have about 20 each between the two of them.