Tons of them: MLS, NDC, FARES, Dataquick (now part of FNC and includes AIRD which incorporates the old CMDC).
Always have the MLS. Always. After that, choose your poison for public records. You can get transfers, property data (be careful- not always right), plat maps and flood zones from NDC, FARES, and Dataquick.
As a word of caution based on the info that Data Quick has for Arizona. If there is more than one structure in the assessor's records in Arizona, Data Quick reports only the last one entered. So a parcel with a house and a separate storage building would report a property with a 100 square foot storage building only for example and there will not be any info on the house in Data Quick. I have been extremely upset with them for years about that, sent them info for four counties, samples of other reporting services, samples of other reporting services in other states and they still haven't corrected their CDs. So check out how they report assessor's info in CA, according to them, Arizona is the only state in the union that has more than one structure on a single parcel!
MLS and NDC gets all I need. I have always had the a question though, you see the San Diego MLS (sandicor) also has tax records available. So IF I use the property listing from MLS and obtain the county tax record VIA the MLS service does this qualify as two "Sources" if not why not? The point is moot because I have to go elsewhere (NDC) for plat maps anyway so I end up paying the money.