Vector/polygonal, truly implemented for the technical benefits* and likely untextured**. Which will make it more niche than the early 3D stuff that did use vertex colors.

3D polygonal+vertex color actually isn’t that difficult to do. I’ve done some, the real issue (aside from making it good) is actually the animation/game around it. I haven’t done much and continue not doing much because personal stuff.

2 examples (of my own stuff) I've used many times before

Image Image

* less data while also rendering at native res without needing extra work (8K or even on a 50ft Billboard? Sure). MIDI (you can use higher-quality soundfonts) or other procedural stuff (sounds, textures) are nice too.

** I’m not against not-too-many general-use textures, but I tried this without mapping (including watercolor) and wasn’t really happy with the results… plus normal maps won’t work with per-vertex materials¯. So this probably takes a lot of effort/skill to work as-intended.

¯ not strictly necessary, but I don’t mind the idea aesthetically and a free optimization sounds nice even though this aesthetic is already a low bar (unless it could help with webGL, mobile, VR, or really old devices etc?)