dbat 
Tip: In Godot 4.4 there's a new snap-mode in 3D. Use Shift+G to enable it.
Note: You need a StaticBody and collider on the mesh you want to snap to! This took me ages to figure out.
After that, SHIFT+G and drag an object around and it will use rays to snap to surrounds.
Ctrl and Shift to modify the usual grid snapping.
Nice!
🦇