Interior live oak, Q. wislizenii, is great bonsai material, similar to coast live but with rough bark. Valley oaks are also good. Leather oak, Q. durata is a good subject with tiny leaves but hard to find good bonsayi subjects. Blue oak, Q. douglasii make beautiful bonsai but can be tricky in pot culture and collected trees are difficult because they tend to have very deep roots. Canyon live oaks. Q. chrysolepsis, are great for bonsai but not seen that often. Oregon oak, Q. garryana, grows in Cal. It is similar to valley oak. Oaks also hybridize frequently so sometimes very nice, unusual stuff can be found. There is a type of coast live found around Santa Cruz with very corky bark.