Soup - I have a multicooker/instant pot type thing so takes 10 mins to prep then leave it to cook while I'm working.
Omelettes
Jacket potatoes in the slow cooker. Rub with oil and a little salt, wrap each one in tin foil then cook on high for 4-5 hours. So if I prep them at breakfast time they're done by lunchtime.
Toasted sandwiches - ham & cheese, or smoked chicken, cheese & chopped sundried tomato
Quesadillas - made with chilli beans, cheese, a little salsa on top
Pita, falafel, salad, Greek yoghurt, mint
I got a breadmaker when Covid first hit and it's been a game changer for WFH lunches. Stick everything in first thing in the morning, hot fresh delicious bread by lunchtime. I like experimenting with adding different flavourings, I quite like adding a spoonful of wholegrain mustard and a big handful of chopped fresh herbs from the garden.