The last time a near TPK ended up happening only 1 party member was alive and they had enough scrolls of revivify to revive all but 1 party member. That remaining party member challenged the avatar of Death to a 1 on 1 fight to come back to life. They barely succeeded but they ended up winning.

Basically I've got a lot of extra rules about things if a player end up dying that they can pick from in the event of death. I have them pick it during character creation as part of adding more depth to their characters. It usually ends up being pretty cool.

Funnily enough my players usually only get close to death when fighting creatures instead of intelligent beings. They seem to have a knack for it at this point.

Well planned encounter that the party comes across on their current quest?

Smashing success, barely an inconvenience.

Random encounter from random encounter table

Fight for their lives, knocking on deaths door.

You can also just do this mechanically - enemies use their actions to discuss taking prisoners, stabilize the dying, tying them up. Hell, even beasts can drag away unconscious members to eat later rather than going for the coup de gras. One further, once a player is on the ground, smaller animals might decide to tear apart their backpack for the rations inside.

The undead attacking the downed player touches them, have the player roll a constitution save, declare they fail (unless they roll a 20), and the undead vanishes/disintegrates. Now you have a stable player and a mysterious ailment to use as a future plot hook/leverage.

You could also let them die and have the campagin continue 50 years later with a different party after the bad guys have taken over.

Personally, I'm a big fan of making my players wake up in Hell and having them figure out how to escape.