I have compiled a partial list of 6SN7 subs. Note not all are exactly electrically equivalent.
6SN7(W) 6SN7 GT, GTA, GTB, WGT, WGTA, WGTB
5692
VT231
CV181, 1988 (= GTY) ...GT. Britain
ECC32, 33..............GT. Britain
33S30A, 33S30B ........Swedish Mil Spec
6N8S, 6H8C, 1587.......USSR