Toyota 86 and Subaru BRZ are basically the same car. The car was designed by Toyota while Subaru supplied the engine. Just one example.

I think Toyota also owns a significant amount of Subaru, probably other mfgs. as well, Toyota is the 600lb gorilla of the car industry.

Sure. Mazda’s CX-3/5/9 in the aughts and early teens often had licensed Ford engines. The current Ford Tourneo Connect has a wholly VW-manufactured engine.

It’s probably most common when an automaker introduces a new make and wants to save time and capital on developing and getting into production a new engine.

The last model of ford ranger and Mazda B series light pickup trucks were mostly the same except for the badges.

The Toyota matrix and Pontiac vibe used a lot of the same parts shared an engine and drivetrains if I'm not mistaken.