I need cold lunch recipes for work

It really depends what you like to eat. I find shredded chicken and veggie with cheese in a pita or wrap pretty filling. I'll often bring a cold pasta or grain salad often - pasta, barley, or farro with chopped crunchy veggies, chickpeas or white, black, pinto beans, shredded tuna or chicken, and an oil & vinegar type salad dressing.

And sometimes I bring PB&J on rye with carrot sticks and a yogurt!

No recipes will "help with weight loss", it's all about the calories. If you're logging your food accurately and consistently, you should get a good idea about how many calories to spend on lunch and tweak your serving sizes accordingly.