The more types of habitat your yard has, the more types of wildlife you will discover. A rock pile is very important if you want to attract toads, salamanders, lizards, and even birds if you've got large rocks. It gives them a hiding, nesting and feeding place with protection.
As you find rocks in your area or visit other areas that allow you to take rocks, keep the rock critters in mind and build them a place to reside.
You can add one feature at a time to your yard and build gradually. Any thing you do will benefit some form of wildlife which will make you and them really happy. Get more ideas on creating a backyard habitat.