061 Steyr 640 - it was also (or first of all?) used as an artillery tractor for AT guns
Bulgaria also used (confirmed on photos):
- Maultier tractors
- 45 mm M.1942 AT guns (after the war?)
- 152 mm ML-20 gun-howitzers (after the war?)
- 100 mm BS-3 heavy AT guns (after the war)