80 Days - it’s not free but I think it’s worth it. It’s a sort of steampunk version of Around the World in 80 Days where you have to plan your routes, and buy and sell things in different cities to make money. The main gameplay is sort of choose-your-own-adventure events that happen during travel and in different cities.
Card Thief - I just started playing this recently. It does technically have a microtransaction but it’s more like, they let you play for free if you don’t mind waiting for chests to unlock, or you can buy the game to bypass this. The main gameplay is sneaking through dungeons represented by a 3x3 grid of cards randomly drawn from the deck; collecting treasures and avoiding getting caught.