I have a list of unique items form a much larger list, using the typical formula

=INDEX(Data Dept,MATCH(0,INDEX(COUNTIF($B$5:B6,Data Dept),0,0),0))

But to avoid a string of trailing #NA's I enclose that in an iferror() to show blank (looks empty, but of course is not) results:

=IFERROR(...,"")

I want to put a count of the unique items at the top of the list, but all combinations of count, countif that I try just give the entire list length including these blank cells - not the actual unique items found.