Praxis Arcanum is a deck-building, multiplayer storytelling rpg about settings shaped by weird power. You can play anything from X-Men to Grisha with it---your setting just needs to involve a power that folks can access that is outside the range of what people can do in this world.
The PDF is 62 pages, with solid layout and some helpful illustrations.
Mechanically, Praxis has some solid crunch on it. In the same style as Fate Of The Norns, you build a deck of standard playing cards for your character, then draw hands from it. Playing cards of a suit allows you to pass skill checks relating to that suit, and the more cards you play at once, the stronger your attempt is.
This makes the ratio of cards in your deck matter, so if you're heavy on hearts, you'll have an easy time of passing hearts checks, but you'll be less likely to draw the cards you need for others.
However, playing cards means marking experience on cards from a 'buy list' that sits next to your deck. Accumulate enough exp, and you can buy more cards into your deck. Get enough cards of a certain suit into your deck, and you unlock new passive and active bonuses.
It's all very cool, although it involves marking the heck out of multiple decks and sometimes genuinely destroying individual cards, so probably don't play this with decks you want to keep pristine.
The GM also has a card deck, by the way, and plays a slightly separate minigame where they draw cards to apply obstacles and complications to the story. It's neat to see the GM position being lightly gamified like this, but it doesn't ever seem to turn into oppositional gameplay. The GM is still not ever out to *get* the players, a la Descent.
Overall, this is a really cool engine that turns several decks of standard cards into the crunchy core of a fun, mini-campaign-oriented rpg. It packs a lot of the fun of a deck-building game into a storytelling framework, all without requiring you to buy custom cards, and for that alone I'd strongly recommend it---but it's also well-written and has good GMing tools.