Ummmm....I don't know. Some monitors use them. Definitely the WG v1001. Electrrohome G05 series (801, 802, and 805), WG 6100 all use them in the HV supplies.
And maybe some linear supplies. Because it's an 80V NPN. (That's why I need them. 2n3904 is only 40V and I have a 65V application...