Wilkinson had a true double sided hollow ground blade, and Miwa from Austria (later could be a wedge, can’t remember). Ronson is also more of a double sided wedge.
I'm pretty sure I have a box of vintage Rexall blue blades that were advertised to be hollow ground. I will have to dig them out to check. I think I tried shaving with one but it was so long ago I really don't remember. They do look really cool though.