Just use:

 

=STACKARRAY(ref_to_your_array)

and stack your columns instantly wherever you need it in your spreadsheet. Without altering the initial array.

Remove blank cells

 

=STACKARRAY(ref_to_your_array, TRUE)

Stack row by row instead of column by column

 

=STACKARRAY(ref_to_your_array, , TRUE)

To merge an array with unique values only, use

 

=UNIQUE(STACKARRAY(your_array))

To sort the resulting column, use

 

=SORT(STACKARRAY(your_array))