My go-to for lunch is always just:
Olive oil
Red wine vinegerette
Salt, pepper, oregano
Very simple and easy and tastes great.
Sometimes if I'm feeling fancy I'll make Caeser dressing. I've been using this recipe on bon appetit for years now and it does not disappoint!
https://www.bonappetit.com/recipe/easy-homemade-caesar-dressing?intcid=inline_amp