Coincidentally I was specifically looking for metric O1. First in euro suppliers (spendy) then Ebay (slim pickens) then in my usual dark alley (AliExpress). If 'tool steel' is there, its well disguised. They have reasonably priced HSS as in cutting tool blanks. All kinds of carbide in many shapes. Hardened tool steel (I guess shafting & ground blanks?. But yet to see classic O or W or A. I've tried as many keywords as come to mind: O1, A2, oil, water, air, with/without 'quench', high carbon, tool steel, annealed. soft... No hits. Yet you can find oodles of finished products that were obviously made from the stuff. Surprising really, they offer stock in so many other alloys. Now would it be real or come with a spec sheet... the usual disclaimers. First it needs to be found. Maybe this is the domain of Alibaba not AliExpress?
Maybe the Bladesmith crowd has some sources, these prices must be killing them