Culturing slime moulds in moist chambers is a tried and true method of surveying for myxomycetes. It’s easy and fun to do!
A magnified glass or x10 hand lens (loupe) is required when searching for the tiny fruiting bodies, but this is much easier to do with a microscope with x20 to x 40 magnification.
Here are a couple of links to articles describing the method:
How to Create a Slime Mold Moist Chamber