warframe used to be. but it's near-impossible now to start & get through even the first major 'holyshit' moment without having it at least partially spoiled before hand.
TBF, Warframe was far from a free-to-play tier experience, at least back when I played it. The Second Dream is still my favorite story quest in any game I've ever played
Seconding this. It's really an exception to the rule in every way. Pretty much an exception to every rule really for better or worse, the game barely tries to be liked or to even make itself comprehensible.
You have warframes, the tenno, flying wings that attach to your character in space and in the open worlds, capital ship combat, the necromechs, the hoverboards, fishing, rougelike world, pets, soon also the protoframes with their AK-47s, an insane story involving truly Kojima-esque named characters like The Man In The Wall and maybe gay love(?) and some character choices like the one with the hole for a face, bird, or brutalism.
You don't even have to play it multiplayer either. You can solo just about everything.