Torchbearaer has 33 in the core book, 8 more in the LoreMaster's Manual, 1 more in the Scavenger's Suplement, and then 5 more non-joke ones in the NPC lists in the Scholar's Guide (Beekeper, Brewer, Glazier, Miller, Potter). That's 47 in total.My Runequest and 5e hacks have 50 skills. I consider this the minimum number of named proficiencies for a skill-based game. If you're going to have fewer than 50, then the game should be attribute based. Some people might think it's obvious that I run a lot of Burning Wheel.
Prince Valiant has 14 basic skills and 15 advanced skills, or 29 in total. In our game we ignore Spoken Language as a skill, so that leaves us with 28.
In the Classic Traveller ruleset that I use, I have the 23 (it might be 24 if you break Ship's Boat out from other Vehicle skills) skills of the 3 core books, plus another 20 from the various supplements, or 43 in total (Although there are more than that if you count all the options for weapon skills and Vehicle skill as cascade skills).
I think all of these are fully functional as skill-based games. Of course so is Burning Wheel - but one thing that I think makes BW's long skill list is that it has a decent rule for synergy/augmentation, namely, FoRKs.
I think that nearly every RPG system that I play has more descriptors than this: as well as the ones I've mentioned there is 4e (combat rolls, plus 17 skills), and Marvel Heroic RP (19 categories of power, plus 13 "specialties" which are a bit like skills). The only exception I'm thinking of at the moment is Agon, which as I posted upthread has 4 "domains" of competence.It seems to me that designers of a game should figure out about a dozen() distinct things that are *actually rolled in the game and make 'skills' for them. If it's not rolled often, fold it into another 'skill' and make that beefier.
(*) Actual number can range, but I think a dozen is about right, give or take, depending on the game.