Rectangular bounding boxes would be best for being non-computationally complex.Not built-in, you'd essentially have to write your own collider system based on mesh limits to do it and that would get computationally expensive on a complex mesh. It should be relatively simple to apply those interactions to the unity colliders as long as you know the impact point and speed.
Update: I was wrong, here's some code that does it straight from the vertex data but its still computationally expensive on a complex mesh.
https://forum.unity.com/threads/raycast-without-colliders.14378/