I like to have a Tupperware of veg ready to eat in the fridge at all times, it makes for a really easy side or just plate some for a quick snack. The one in there at the moment is little gem lettuce, grated carrot, pink pickled slaw, sliced peppers and cherry tomatoes. During the winter I would have greenbeans, asparagus, mushrooms, babycorn, sugarsnap peas and would just steam it in the microwave for 3 minutes to have as a warm side or with a couple of boiled eggs chopped and mixed through as a warm salad for a light lunch.
I am also a huge fan of my slow cooker, I make up a batch of something that includes 400g meat and as much veg as I can squeeze in. That will make 4 portions each one about 200-250 calories and can be a lunch by itself or paired with some basmati rice or a steamfresh bag of veg for dinner.
My current batch is pulled chicken, I buy prepped veg so just need to empty into the slow cooker and turn it on, 400g chicken breast, 2 bags of sliced mushrooms, 1/2 bag of frozen sliced mixed peppers, 1/2 bag sliced carrots, 1 bag sliced red onion, 1 can of chopped tomatoes, a couple of tablespoons of chia seed for added fibre, whatever seasoning you like I think I used old el paso tomato and roasted red pepper, on low for 4-6 hours then I put it on the hob for 10-15 minutes to thicken up. The chicken breast shreds apart as you stir.