I've used the isopods called powder blue, they seem to breed pretty fast and are decent sized. For the pill bugs, I have 3-4 boards from untreated lumber laying around in the weeds in my backyard. I can lift those up and harvest a bunch that way, when it's not too hot sometimes there are earthworms in there, too. Sometimes snakes hide under the boards which is also fun to find but most times I can get a lot of pill bugs that way.