DH uses these lunch containers:
Ello Duraglass Glass Food Storage Meal Prep Containers
https://a.co/d/bb6ZhiJ
I usually meal prep for him on the weekends (while he does all the laundry, so we’re even!), and make one big meal to divide into those 5 containers. That way I’m only cooking the one thing, not several. His current favorite is yellow curry chicken & potatoes over rice. He also likes burrito bowls, lentils over rice, and pasta salad.
When I was in the office, I preferred packing a bunch of small, no cooking required foods — salads, hard boiled eggs, cheese, nuts, fruit, crackers, etc.