Both SAME and Fiat made their own engines, in the 70's models you show in the pictures.
Fiat is the mother company of Case-New Holland, the smaller engines are Iveco branded, which is the name of their truck and engines division.
Same is only building its air cooled diesels for certain countries, and certain lower hp classes where the stringent emissions arent phased in yet.
Same took over Lamborghini (the sports car manufacturer used to be a tractor manufacturer, but sold the tractor division to Same) and Hurlimann from Switzerland.
Later they took a share in the ag division of Deutz-Fahr, in which they later took a majority share. The implement line was sold to Kverneland, and the Deutz engine division is owned by Same, Volvo and some smaller financial investors. The Deutz marine engine division is also sold to private investors who have resurrected the name MWM, which was taken over by Deutz in the 80's. The MWM do Brazil company, tied up with Navistar, supplying diesels to Ford pickup trucks, used to be a subsidiary of MWM when they still were independent.
Zetor used to build a 2023, which was a 25 hp narrow crawler intended for steep vineyard hills. Their 50hp standard size Super P crawlers were discontinued after 2 years, as a political fate, in favour of competing Soviet designs.