Sumeria – Arguably the world’s first civilization, developed one of the earliest forms of writing, were pioneers in metallurgy, discovered the wheel, developed social classes and organization, cities, trade networks. They also developed military organization and learnt how to farm through irrigation to feed cities and armies.
Phoenicians – Improved ship building and were thus pioneers in maritime trade.
Jews – Introduced monotheism. They also created a sophisticated ethical code.
Indo-Europeans – Introduced Iron working and domesticated horses. This enabled them to develop war chariots.
Sumerians contributed more towards human civilization. This is because they introduced human civilization itself. They also made more contributions across divergent fields than any other civilization.