Selecting whole column except first X (header) cells in Excel

I know I can select all cells in a particular column by clicking on column header descriptor (ie. A or AB). But is it possible to then exclude a few cells out of it, like my data table headings?

Example

I would like to select data cells of a particular column to set Data Validation (that would eventually display a drop down of list values defined in a named range). But I don't want my data header cells to be included in this selection (so they won't have these drop downs displayed nor will they be validated). What if I later decide to change validation settings of these cells?

How can I selection my column then?

A sidenote

I know I can set data validation on the whole column and then select only those cells that I want to exclude and clear their data validation. What I would like to know is is ti possible to do the correct selection in the first step to avoid this second one.

I tried clicking on the column descriptor to select the whole column and then CTRL-click those cells I don't want to include in my selection, but it didn't work as expected.

Click on the first cell you want to be selected and then press Ctrl + Shift + ↓ to select a block of non-blank cells, or a block of blank cells (including the first non-blank cell below it), downwards.  Press again to extend the selection through further blocks.

This may cause the top of the worksheet to scroll off the screen.  Press Ctrl+Backspace to scroll back up quickly.

Universal

=SUM(A2:INDEX(A:A, ROWS(A:A)))

or

=SUM(A:A) – A1

Both will return summary for "column A", except for header in A1