HC-110 concentrate from before about 2019, as far back as the 1990s (maybe longer) is almost certain to be still good -- even in partially full bottles it's likely to be fine. Same is true for genuine Rodinal and most of the Rodinal clones (A09, Apodinal, Adonal, etc.). Most toners (selenium, sepia, thiourea types) will last approximately forever in closed bottles; though bleach-redevelop color toners are less durable, if they're just the dye and dye coupler type they ought to last many years (it's the liquid developer that can fail). Fixers in liquid form will tend to sulfur (decomposition of the sulfite, then of the thiosulfate via sulfite) but I'm currently using Kodak Rapid Fixer from a concentrate bottle (set) that was originally opened in 2005 or so. Stop bath lasts forever if not being used.
Dry developers (that is, bags of dry chemical to be mixed with water) will last a very long time as long as the bag is airtight (I'm currently using Xtol that I mixed a few weeks ago, with a 2002 expiration on the two-envelope package).