This is a weird one but … size 10 knickers. Seriously, I’ve been into K-mart on three separate occasions, and they have EVERY other size each time (this is cheapo five-packs … I’m sure the expensive match-your-bra styles still have All The Sizes)
Hand-weights are also still nowhere to be seen. Though a little bird did tell me they get new stocks in every Wednesday, but the vultures have cleaned 'em out by evening.