Add an existing block by type of block

Hello,

Problems :
We have a lot of custom block for our site. It's difficult to find a block with only one autocomplete field for all types of blocks.

Solution :
It will be great to add block like we add node today,
add a line "block" below "Entity block"

When we clic on this line, have a new tray for chose a type of block

Then a final tray with autocomplete field for this type of block.

Best Regards,
Quentin.