Cold bento lunch ideas?

Hi y'all! Just a quick question with some background. My hubby works out in the field and doesnt have a way to keep his food warm or have a place to warm it up. He's getting a bit bored of just sandwiches so I'm planning on making him some bento-inspired lunches but am running low on ideas of foods that are good to eat even when they're cold. For my lunches its not a biggie as I'm in the office and can eat anything, but he's a bit more picky when it comes to his meals. Does any one have any ideas on some cold bento-inspired lunches? Thanks!!!