/block makeFall
This is a command that lets you modify preexisting blocks, converting them into groups of falling entities.
/block makeFall <pos1> <pos2> [<nbt>] [<time>]
Syntax:
Pos 1 / Pos 2
/block makeFall ~5 ~5 ~5 ~-5 ~-5 ~-5 {} 1t
This lets you choose a range of blocks that will be turned into falling entities, you could just do the same position twice to only make one block fall.
NBT
/block makeFall ..... {Tags:["tag1","tag2"]} ...
This lets you edit the nbt of the falling entities that are created. Letting you give them tags and such. This is the same nbt that you'd use when summoning one the normal way.
Time
/block makeFall ... 50t
This is a super cool Utility exclusive where you can add a timer that prevents the entity from turning back into a regular block upon hitting the ground for a set amount of time. Letting you do things such as throwing it around with /velocity.
/block makeFall ~2 ~2 ~2 ~-2 ~-2 ~-2 {} 1t
/block makeFall 5 20 5 20 30 20 {Tags:["falling"]} 50t
/block makeFall ~ ~ ~ ~ ~ ~ {} 9999d