I was always pulling hair when I try to mount figures. The usual wooden plaque or acrylic disc can only get you so far, but a full blown diorama base is not scalable when you build a lot of kits. This is where the woodland scenic rock moulds are great. Since it’s a mould you can reuse them over and over, and you can mount figures on them in different ways or paint them with variations so that they don’t all look the same. The moulds are inexpensive, and cost around $8-9, and you can get them via hobbylinc.com.
I use plaster/gypsum to cast them. On the right is an almost painted cast of my favorite mold, modified on the front to support my upcoming Kanu figure.