A native I am curious about after seeing a couple pretty sweet ones while hiking is Antelope Bitterbrush (Prushida Tridenta), which is in the Roseaceae family. Small leaves, gnarly trunks when older, nice flowers. Maybe kinda leggy. I can see some similarities to potentilla, also roseaceae, in the trunk and flowers. The little I have found as bonsai, specifically yamadori is they tend to have deep tap roots and likely difficult to collect successfully.
Here is an awesome one that really got me looking at them. In the spring I will check its viability to collect but likely leave this one until after I mess with some less impressive examples. Nothing for scale, but this was about 26" tall. Its hard to see but the taper and twist in the trunk makes an amazing informal upright already. Almost just seems like it would needs strengthened and thinned out.
Example of leaves, not peak season. Link below can show you flowers and fuller examples.
General info regarding using them in landscape