AFAIK, early MS-DOS made heavy use of the technique, probably(?) before EMS/XMS became available/common. "OVL" popped up in my head for some reason, and https:

AFAIK, early MS-DOS made heavy use of the technique, probably(?) before EMS/XMS became available/common. "OVL" popped up in my head for some reason, and https://www.google.com/search?q=dos+ovl https://www.google.com/search?q=dos+ovl seems to return interesting results (showing a few real-world examples).