I don't think I have any original solutions. About that plant pot hide, I just knocked a notch in the rim with a hammer, filed down the edges and put it upside down. It got a crack in the process but holds together anyway. The hole in the bottom of the pot is big enough for the male to get through it and I shoved a fake plant into it after I got the female.
A piece of bark between two rocks or just with the substrate dug out from under it. Very basic. And I have a piece of cork bark about 40cm long that's almost like a hollow log. In the corn snake terrarium I have a folded air pistol target and a cardboard tube with a couple of extra holes cut into it. And then there is the "bird house" type hide I made from a wooden sugar "jar".
Not to mention that I was dumb enough to pay for a coconut hide.