if I'm not confusing it with some other OS, I think there was an emulated TOPS system online not so long ago
There are, however, publicly accessible TOPS-20 systems, including one at SDF which should be soon available moved onto recent~ish made physical PDP-10 system (a TOAD-2 PDP-10-on-a-Chip)
Plenty of files from TENEX tapes are here: https://github.com/PDP-10/tenex