An excellent idea and generally useful to us (we have a septic tank) I did a bit of digging on biodegradable cleaners. There are a surprising number out there with a surprising range of prices. Ease of purchase and delivery costs are also an issue as many are available mail order only.
What we have in the house at the moment are OzKleen products as these are available, relatively cheaply, from our supermarket. I’ve not yet used them in a decorating capacity, but I’d be more than willing to try.
Understandably, it’s difficult to obtain ingredients lists, manufacturers not wanting to give away their secrets, however, p series glycol ethers are a candidate solvent.
The ease with which biodegradable cleaners degrease does cause me concern. I wonder whether in 10 years time there will be a new family of chemicals added to the harmful list. However, for the time being they do make life easier.