I don't know if it's properly "unpopular" or not, but in my home game, PCs do not face unplanned, permanent, irrevocable character death. Dying to a random orc's critical hit would not happen in my game, unless the player and I agree about it (and I usually favor the player's preference, though if I think the character has a reason for sticking around, I'll speak up for them). I've gotten a LOT of flak about this one every time I mention it--people instantly assume it means my game has zero stakes, that it's just an infinite wish-fulfillment fantasy with no actual difficulties or obstacles. The times I've mentioned this to my players, they thought that was either hilarious or deeply confusing.
Because I don't have a game with zero stakes. I have a game with very dramatic, difficult stakes. "Do I get to keep playing" is not one of them. Instead, it is deep questions of moral character, challenges to a character's intelligence or wisdom or creativity.
I have challenged the party Bard, not by putting him under threat, but by making it so he must choose between purity and helping others. He chose twice to help others, even though it meant taking dark and dangerous powers into himself, and now that binds him to nefarious things that he will have to grapple with later.
I have challenged the wide-eyed wanderer Druid with having to keep dark secrets from his trusted friends, and having to kill some very bad people...because a devil asked him to. He eventually chose to be honest, despite the toll, and then to trust others, despite not knowing what the future held--and now he has been challenged with a much different and deeper mystery.
I have challenged the party Ranger with power and temptation: he was (and in theory is) an ardent critic of his orc grandmother's decision to move her Nomad tribe into the city and begin integrating into city life...but now he has had his ambitions justified by proof that he is (in some spiritual sense) an heir of the First Sultan, and has decided to begin creating his own city-state. Far from abandoning the comforts and controls of the cities, far from repudiating the debauchery and moral turpitude of his human grandfather, he has slowly begun to embrace and become these things, and developing some rather "rich-man" habits (like becoming a connoisseur of fancy tea).
Edit:
And to be clear, none of this means losing doesn't happen, nor does it mean that characters are completely unable to die. It does, however, mean that if a character does die, it's not permanent and irrevocable unless the player is okay with that. A character may die...and then "wake up" in the Land of the Dead, and have to find their way back to life. Or they may die...and then suddenly get sent back, without knowing why. Or they SHOULD have died, they very clearly should've suffered a mortal wound...and yet they're still alive. Why? How?
Answering those questions is, as far as I'm concerned, a thousand times more interesting than creating a new character if the player would prefer to keep playing the character they currently have. I actually talked the aforementioned Druid out of killing off his character For Real. He needed to depart the game for real-life reasons, and wanted a "big finale," thinking that a death would make sense. I talked him into doing an ambiguous, "Elijah taken up in the whirlwind"-style ending--something that could quite easily keep the character away for a completely arbitrary amount of time, while also enabling a return if he thought that made sense later. And it turned out he did, so he's now back, and he's an active party member now.
It reduced the amount of house-rules we needed to accommodate the 2d10 system.
