What is a good flat super tool bookmark?

Beyond reading books regularly, I carry a journal/organizer composition notebook everywhere I go. It helps to be able to turn to the right page fast. I am looking for a bookmark that does more than just mark my spot. It needs to be flat, safe, TSA approved, shaped in a way that doesn’t take up the whole page, and uber useful. So far I have thought of the gamut of measuring objects like rulers, and stiff cards that have info. printed on them(grammar, measures, periodic table). Have any thoughts. I like the periodic table Idea.

Anyway, it will have front and a back if it is a laminated info card, so if you can think of some nifty stuff besides a ruler to put on there that would be great. Thanks. Also this is likely going to be the replacement for my idea of having a tattoo with useful info on it. Check that question if you like.