Geometry nodes (idea for physics nodes)

Now that we got Geometry nodes, inside Blender.
I think it is a good idea, to include lots (say 50+ or so) of example recipes in it.

The next thing is probably particle physics, and that one currently has lots of usages. There should be ways to do the old things we're used todo in a simple way.

Maybe to do it easy, build pre-made groups (as in cycles node groups) that emulate as much as possible to current behavior. So we can make our explosions, boids, particle fluids, smoke, hair types as we used to do.

You-know-what, even the geometry nodes might benefit from premade groups.