My wife is into soaps without lauryl sulfate so she buys soaps from Neways (US site). One of the products is a shaving cream which has been designed for the main stream 20 blade razors :-).
I have found it to be terrible for straight razor shaving. I am not sure what it is doing or not doing but it doesn't do anything to the whiskers and succeeds in promoting nicks and dulling the razor edge. Unless someone tells me to the contrary I will not be using it again.