In 2020 I started a new line of 3D models - cartoon style race tracks. These tracks are designed to work well with my car models.
This is the gallery of my Cartoon Race Track models available, with new locations added every month or two. All models are royalty free to use in your game project, animation or visualization. Purchases can be made either in Unity Asset Store, or Sketchfab. You will find links to stores on page of each track.
Unity Asset Store downloads include texture files in .PSD format with unlocked layers. This will allow you to make any modifications necessary to make the track look individual to your project.