Way back at the beginning of time I was a Realtor in California. The California Department of Real Estate published a DRE approved 'standard' sale agreement. Many companies used precisely this form, added their logo and then made an addendum that addressed special circumstances in their particular market area (zoning, water conservation etc). That was in a jurisdiction where attorneys were rarely if ever used in real estate transactions (we had escrow companies and title companies doing the transfer work). So - these things did exist at one time and probably do somewhere. The thing is that they are very area specific, would not apply from one jurisdiction to another and the fact that you can buy one does not mean that you have any idea how to use one. Kind of like that legendary piano ....... to own a piano is not to be a pianist.
IMHO - when you go to a new place, hire a professional to represent you.