cold lunches that actually taste good and are not boring?

EDIT: thanks everyone, there's some great suggestions in the comments! I don't think I've ever gotten so many comments on a post lol but anyway I especially like the chinese/japanese inspired ideas, I will for sure try some of them and others as well, thanks again :)

I need to bring a packed lunch to work and we have a fridge but no microwave, so my options are limited to cold or room temperature food (which I'm not a fan of). I usually eat spicy stuff and I like strong flavors but cold food tastes so bland to me, no matter how many spices I throw in there.

I've tried sandwiches (they're ok), pasta salad, rice salad, lettuce salad, I also tried cooking my regular food and eating it at room temperature but it just makes me sad because all I can think about is how good it would taste if it was warm. The best I've had was vietnamese spring rolls with peanut sauce, and kimbap style rolls.

maybe I just don't know any good cold food recipes? pls help a foodie out, I can either make it the night before, or the same morning if it's a simple recipe.