I can only think of one private scheme in this space that's worked well - 80 Plus. For a voluntary program, it's been pretty broadly adopted, and it created an implicit factor of "why is it not certified" that puts pressure on the worst junk products.
Across the board though, PC PSU quality has gone up quite a bit in the last 20-25 years though.
80 plus doesn't cover idle efficiency though, so unless you only run your computer when compiling or gaming and then turn it back off, it probably doesn't capture the fact that modern computers are basically completely idle at all times.
UL certification has been pretty successful in an adjacent space (fire safety, notably of electronics but it covers other things too). That has been regressing lately, though.
Across the board though, PC PSU quality has gone up quite a bit in the last 20-25 years though.