I apologize upfront as this is probably a very simple thing. I'm either over thinking it or just not getting something.
(it'll probably take one of you a second or 2 to figure out)
I did the search and reviewed a lot of suggestions / solutions - some of which were more complex as some were looking for unique values based on some other criteria.

What I have is a list that continues to grow (it could be a list of 1,000 today and 2,000 in 6 months). I'd like to be able to have a formula at the top of a column that outputs the unique count of instances in that column.

Please refer to the attached example...
Thanks in advance!
CountUniqueValues-1Column.xlsx