I have several matched hollows & rounds…but I don’t have a full set. Or a half set. Poor me. (That said, I do have the two sets I knew I would use, plus a couple unusable ones inherited from my grandfather.)
Anyway…I don’t think a half-set is unreasonable for anyone who pursues hand-tool woodworking. So these aren’t really be an indulgence so much as something you might just have to save up for.
Thus, on my list goes a half-set of H&Rs, from any of several makers whose tools I either own or have used enough to feel comfortable recommending them (with the caveat that not all of them are taking orders…but if you run across their wares in an estate sale, snap ’em up!): M.S. Bickford, Old Street Tool (formerly Clark & Williams), Caleb James and Philly Planes (from whom I, er, borrowed the image).