Define suitable ?

Are you looking for a basic mechanical diesel with no wiring, or are you happy to dive into a nightmare of wiring ?

For the basic version....and whilst I'm not a big fan. The D24TIC 2.4 diesel VAG 6 cylinder is decent enough.
Typical rwd layout, rear sump ( in a Volvo 940 anyway ), and around 120bhp or so.

I think there is also a 5cyl version fitted to some early Audi 100's that is mostly mechanical.

After that they started to go technical with electronic control.

For a modern one with lots of wires.

There really is a multitude of engines. Dont forget to consider vans too, as some of them will be rwd. eg Merc sprinters and some VW.