Drop-down of common values

[nozense]

This might go somewhat against the norm in how databases are made, but since I would find it useful I thought I´d drop it here to see what others think.
I have a couple of columns in a project that are text-fields and can contain wildly different strings, but sometimes there are stretches of rows that uses the same string in the column, and/or strings that reoccur somewhat often. It would be useful for me if "common values" where presented as a drop-down without me having to make a separate table for the column.

I see this only as a UI feature, nothing to do with the database.