This is a contribution from existing usability improvements that I've used for fields. The key concept is to cater for fields with long lists of options such as:
select (multiple) lists with 20+ options
input checkbox lists with 20+ options
The solution is purely a JS/jQuery solution for hiding and showing relevant information from a filter input.
The user enters a few letters and the options the user is seeking become easier to see from the potential thousands.
The next feature to be ported to the module will be in regards to 'accidental noobness'...
When a multi-select already has options chosen, it should be clear to the user A) what changes they make and B) what's been chosen.
The solution is to simply show a "Was selected: x, y, z" and "Now selected: a, b, c" list when interacting.