Some things are regional, so it's hard to know if it's been discontinued or not.
Campbell's Chunky - Chicken Mushroom Chowder (though I scratch-make something very similar) - been gone for several years
dnL - a green, lime flavored 7up with caffeine - they only made it one year
Swiss Creme brand soda - it's not the same as it used to be, so it might as well be gone
Dean's Extra Rich Egg-Nog - used to be in the dark blue quart bottle - haven't seen it in years, only the regular & lean (
Vanilla creme Pop-Tarts - the ones with vanilla inside & on top - they come back once in a while, then disappear again