I generally go for a quick lunch too, like pps.
I've noticed though that LO2 (2.5) eats better in the mornings than in the evenings, so I'm trying to rebalance things so she gets nutrious offerings in the morning and for lunch. Often the lovely hot meal I've put effort into doesn't actually get into her mouth but she's just not able for it by 5pm. Unless it's pasta!
Quick popular lunch things: omlette, or more often these days frittata (when I roast veg I always do extra so I can make one, very yummy with sweet potato), plently of good old beans on toast, cheese on toast, hummus with roast veg, pizza (a rare treat!), boiled egg with potato bread, soups, lentil dal with flat bread, smoked tofu with flat bread, cheese cubes, peanut butter with crackers or toast. We always have fruit to finish, sliced up to share.