737-200AD (-17's) had the Flap 2 T/O figures provided in the QRH.
Flaps5 was the preferred T/O setting, though on a heavy T/O Flaps1 was preferable. But for a heavy T/O with a downwind component Flaps1 would exceed the Brake/Energy limits in a high speed rejection. The solution was Flaps2, virtually the same T/O performance with the Brake/Energy limits respected. My uneducated guess why the Flap2 position is still there in later models, is because a lot of the 737 certification data dates from the original models.