807 -5933 - 6BG6 - 1625

These tubes are all closely related to the famous 6L6 but have differing electrical characteristics and pin-outs. Some of these may be direct substitutes with adapters but your millage may vary. 

Equivalents and Substitutes:

807: VT-100, CV124, 5933, CV1060, CV1572

6BG6: None

1625: VT-136, CV659, FU-25