Tyler Dunn
Explorer
Most of them, with a few being characters that joined at low levels. Few PCs are 'lost' after revivify is available, as that (or purchasing raise dead) is usually available. As long as the desire is there to continue the game and character, once life magic is available, PCs tend to stay in the game. The Half-orc fighter in the first group is also a replacement PC that stepped in somewhere around 5th or 6th level (I think).
However, deaths have been few and far between in 5E. There have been some (Fying aaracockra monk gets hit and taken to 0, crashes for a failed death save and then immediately takes a turn and rolls a 1 on the death save was the most recent death).
These games tend to be a little meaner than the suggested guidelines for encounter construction, but they're far from all deadly encounters like seen in some games.
So which characters didn't start at level 1?