How to find all unique, matching values betwen two arrays of cells

this non-CSE formula will do the same:

=sumproduct(--($A$1:$E$4=A7:E7))

however, there is a difference in the result of this formula versus @chemistb's if you have duplicates within each block. this sumproduct formula will *not* double-count duplicates within each block; it will only count duplicates across blocks.