This is a paid asset, but now you can download Lightprobe Generator Free.
Detail this asset from Unity Store: Original Link
Lightprobe Generator v2.0 (Latest version)
“If possible, please buy the package to support the developer”
Automatically create lightprobes based on closed volumes using various algorithms.
3 new refinement methods to improve efficiency
– Raycast Physics Based
– Spherecast Physics Based
– Octree BruteForce Based
—— Works without any colliders in the scene objects
Initial point visualization preview mode. Control samples per point, lightprobe offset and many other options.