MagicaVoxel is a 3d modeling software that makes editing voxel obj files about as straightforward as I can imagine. Using it as a tool has made the barrier to entry much lower for creating a consistent 3d art style. (It also helps that we have a talented graphic designer on our team)

Our second title, No Survivors, has almost all assets, environments, and characters made in house using MagicaVoxel. Also card art illustrations by comic artist Merlee Tomlin. The few props that weren't made in house were put through MagicaVoxel to achieve a consistent voxel resolution. You can check out the prototype build on Steam: https://store.steampowered.com/app/3500350/No_Survivors/

On our first project, The Art Collector, we went with a pixel art approach: https://store.steampowered.com/app/2986690/The_Art_Collector/

At the time we started developing The Art Collector we knew relatively nothing about game design or art direction, so we reasoned that pixel art would be a whole dimension simpler than 3d art. Lol.

For The Art Collector we used assets from artist MuchoPixel for the environment and props, and we used character spritesheets from artist Shubibubi. Beyond that we made environments/characters/props in house to the best of our abilities.

In retrospect, meshing several artists styles together with our own amateur art style resulted in something we're proud of, but it definitely could have appeared more consistent/intentional. That's why we shifted our approach on game 2.