First thing I thought was "SARDINES"! But then I saw
@Chdamn already posted that right away.
A lot of people don't think "canned meat" for some reason. In fact, so few seem to think of it that the canned meat section of the grocery stores seems to be the last hit when people panic buy during emergencies.
For bulk, canned chicken and tuna are my go-tos, as they work well with other canned veggies to make quick dishes. You can get them in pretty decent sized cans, and pretty cheaply as well. Walmart's Great Value is fine for this.
For snacking at work, I usually have a few pouches of StarKist chicken or tuna creations. About 2 1/2 ounces in a variety of spiced flavors...like buffalo style, sweet & spicy, etc. Definitely more expensive than buying canned, but as a snack that keeps me from munching on other things, they're tasty and hit the spot.
Vienna sausages are great. Lots of memories of me and my father-in-law snacking on them while off working on something.
You can also find canned beef and pork. I've seen Keystone and Lehman's at Walmart. In nearly quart sized cans, too.
Spam? I never could get into Spam. I'll eat it, but not generally something I've been known to say "Hey, let's have Spam for lunch!"