Looking through my books, so many of the really thick intro to everything books have marinated olives in them. I started doing this, bascially by accident, My aunt had left a large Tupperware container with olives in on the kitchen counter, she had filled it half way up with lemon juice. It completely overwhelmed everything, took over all flavor, basically pickled the olives, In an effort to save them, I started topping the olives with various herbs and olive oil, the result was some of the best olives I've ever had, since then, I often marinate. This particular time I was inspired by what was at the store, Aside from the usual lemon and olive oil, these contain za'atar, an herb mix from the middle east that mainly contains thyme and sumac.
Other possible add ins, red chili flakes, garlic, onions, herbs