This is with higher internal res, of course (as in the original low-res+dithering makes it a lot less obvious). I hope compression doesn't muddy it too much.

Between the vertex-color skyboxes and LoD* (and Universal Interactive) there is overlap here with Spyro. Differing though it doesn't use the extra-loops trick for hard(-ish) edges, instead its skyboxes use multiple** meshes (such as the dump, lake, and power plant).

On top of this, there are a lot of other things using meshes+VC:

• particle-like effects
  • falling snow
  • fancy ribbons fly when you break presents
  • falling leaves after collecting rotten eggs
  • floating numbers (HUD too)
    • and their pop effect, very quick though
  • bees (yellow triangles with a darker corner)
• the loading screen goo effect
• 3D meshes on HUD for eggs
• 2D meshes are often used (with some texture usage)
  • key items, ~~precur~~ nitro eggs (world)
    • these have a pixel-shader glow effect on a transparent outer ring of polygons
  • gadget UI icons
  • flame effect in junkyard minefield
  • dog icon in ski area (buried timer)
• horns + goo-covered horns in whoville
• puzzle answer painting in bell tower (+normal bell color after solved)

3D things in the world are a bit mixed. There are a few things that presumably have no texture (for instance some statues, hooks, parts of the sleigh). Characters do have flat color in textures (face, pocket, belt textures etc) plus vertex shading, so I don't know if they matched the colors there or if characters are entirely done via UV just like the modern trick of UV-color-palettes (or if this distinction even matters that much).

The exception to that might be Max and the ski-area dog that clearly have VC, though I think that's because the textures used (eyes, ear fur) don't actually provide hue like shirts etc.

* just don't play the entire game in widescreen like I did, it messed up the LoD (and the gadget UI element) EDIT: Checking again, not sure how much effect it has on LoD other than messing up the culling on the edges of the screen making it feel worse. I could've sworn there was more mismatch (though I could've also had something else set wrong)

** Oddly, Mt. Crumpit in the picture looks like the verts line up with the skybox perfectly (wireframe view). Though I'd guess that (assuming face-corner VC wasn't a thing) there's a Mt.-Crumpit-shaped-hole in the Skybox. There is however a window in the bell tower that does have a visibly-separate Mt. Crumpit (it's much smaller, like a diorama).