Banggai Cardinalfish are the easiest IMO.
The Challenge with Banggai is getting captive raised fish and identifying a male & female to pair.
Don't attempt to keep wild caught Banggai in my opinion.
Neon Gobies are probably the next easiest to breed but raising the larvae is difficult.
Mosts clownfish, many gobies, some seahorses, many psuedochromis, and I believe even a couple angels. The vast majority of saltwater fish have not been bred and raised in captivity.
Jon