I can provide two massive point clouds for testing purposes if you want :
- the original modern Besancon project (see previous replies) which is fully colored and has around 170 000 000 points for a small urban area.
- an historic reconstruction from the Besancon area I made from historic aerial photography, black and white “textures” with baked ambiant occlusion and something like 350 000 000 points.
Tell me and I will upload the one you want somewhere.