A Minecraft 1.16 datapack to allow player revival, but at a doubling cost per revival.
I created this datapack as I wanted to play Hardcore with a group, but still have a way to recover members who died early, so nobody gets abandoned. The way this currently works is the required price -- in diamonds, by default -- is doubled per death, initially at a cost of 2. This ensures the cost is attainable as you improve, while still making it quite punishing at any level.
There is also a special resurrection spell effect, but that can stay as a surprise ;P.
To trigger a revive, be holding at least the required number of diamonds and run /trigger resurrect
To reset the cost, delete the scoreboard nqh_values.