The finer things, like razors demanded at least Belgian coticule for a good shaving edge. There's a German stone that goes back a long ways too and is finer and has gotten fairly scarce and quite pricey these days. IIRC it's green or blue/greenish, but was so expensive I would have to luck up on one somewhere. I expect this new gen of guys using straight razors has run the prices up. I have coticule, and it's yet being mined. The cutting media in the coticule is tiny garnet (the gemstone). I started shaving with straights not long after I started wet-shaving about six or seven years ago.
I came across an Arkansas stone "surgical" grade and bought it. Might be good for surgery, worthless for razors-at least the chunk I got, and I'm sure that post-dates most of our timeframe.
That's all I got, no idea about the more common edges or more aggressive stones, but I know some of what the barbers and shavers/shaven preferred. Also Chromium Oxide has been around--wait a minute, nope 1838 the French were messing with it (i wiki'd). Probably took a while to find its way to the strop. It's the green stuff-same as in oil-based green paints.
I'd be interested to know more too.