Lizards are fairly common tiny reptilian guys who zip around and enjoy the sun more than George Hamilton (or, if you're younger, Snookie). According to the California Department of Fish and Game range maps, the following lizard species are found in Yolo County.

Common Name Taxonomic Classification Range in Yolo County
Western Fence Lizards (a.k.a. Blue-Bellied Lizards) Sceloporus occidentalis entire county
Southern Alligator Lizard Elgaria multicarinata entire county

San Diego Horned Lizard

Phrynosoma blainvillii Sacramento Valley
Western Tiger Whiptail Aspidoscelis tigris  foothills and the area northwest of a diagonal line between approximately Brooks and Hershey
Western Skink Plestiodon skiltonianus foothills and the Dunnigan Hills
Sagebrush Lizard Sceloporus graciosus foothills

Oh, there are also the Lounge Lizards, but they aren't quite the same thing.

Salamanders are amphibians that superficially resemble lizards, so if you think you've seen a lizard in or near Davis but it doesn't look like any of these, consider whether it's one of those instead.