Something really cool that would be great would be...
Adding BEDROCK, the strongest block in the game that can't be broken by anything, as it would help make long-lasting and indestructible buildings.
One way to do it in-game is: on the anvil, if you combine a block of redstone and stone, it becomes bedrock.
Bedrock is not meant to be a building material.
Bruh, misplace one block and it's over. Also, it can be used for exploits.
Not a good idea for survival.