European OEM specs will typically use the ACEA "A3/B4" spec as a starting point, then add manufacturer specific tests. For example, VW 502/505 starts with ACEA A3/B4 and then adds high temp testing in the 2.0L gas engine and wear testing in the 1.6L, IDI diesel engine. So I would look for OEM specs like DB 229.3, BMW Longlife, VW 502/505, etc in addition to the more generic ACEA A3/B4.
I would consider any ACEA, A3/B4 rated oil to be significantly better than your garden variety API, "SL" formulation.
For HD diesel oils, the Mack EON, Premium Plus and Cummins CES 20078 are probably the most stringent specs to meet. They are above and beyond the generic API, CI-4 specification ....
TooSlick
Dixie Synthetics