AS 2129 - Table Flanges for Pipes, Valves and Fittings

They are commonly known as "Table" flanges, (e.g. Table D) and are usually made from plate or forgings, hence the pipe bore and tube bore slip-on or blind are the most common forms.

The standard table flanges covers nominal size DN 15 (NPS 1/2") to DN 3000 (NPS 120") in Table D, and DN 1200 (NPS 48") in Table E, but flanges up to DN 400 (NPS 16") are normally available off the shelf, 304(L) or 316(L) grades.
The Table F and Table H flanges are also reasonably popular and a range is carried off the shelf.  The other rating classes of Table A, J, K, R, S and T are less common usage than Table D or E.