Emacs

Helm-mini enables acting on the file list by using Ctrl-Space to pick those required, though I don't know if that is the only action to be done on the selection.

Is that behaviour unique to helm's completing read implementation, or do other such functions exist?

I need to create an SQL command from a selection from a long list of databases and need something that can pick them individually with highlighting, so once I press Enter, the selection is passed to a function.

The default completing-read-multiple of typing a match and adding a comma is not suitable for this.

UPDATE

After some more searching I've come across this Embark discussion which may help me in what I need. I just need that kind of functionality in a completing-read command, basically something which lets me mark a list of items from a list and apply some arbitrary action to them.