What gods did people worship before the Jewish god was invented?

A plethora of other gods and goddesses. Greeks, Romans, Mesopotamians, etc, had their own deities they worshipped

I think originally ancestor worship.

They worshipped and worshiped you, the gods, of your demons, but even if you do not worship them, but you serve them with evil, they will prepare a nice place for you in hell, after God has executed you.

Different cultures around the world worshiped the deities as symbols of nature and emotion before the Israelites conflated El and Yahweh.

I doubt that anyone that far back in time attributed 

life and natural occurrences to any kind of a being. 

They probably stood in fear, awe, and wonder 

of everything that they could not explain, and they 

may have pondered what had taken place, but it would 

be more logical to believe that their attention span was 

affected by too many other things. 

To get back to their more simple life at hand, was god.

Every culture has developed religious practices, the Egyptians, Hindus, Greeks, Romans (before Christianity spread), even the native peoples of the Americas all had religious beliefs, deities they worshiped, and rituals they practiced. There were thousands of gods worshiped prior to the Judeo-Christian god.  

It was not an invention but rather a revelation  of the Self existing One. One who is the same today and forever.

Perhaps in those days they may have worshiped Science just as some humans do today and denying the Existence of our Creators.

In the Jewish confession of faith God is portrayed as a Compound Unity.

Supposedly, Abraham's father made his living carving idols, so that would be the immediately-previous answer. However, it is likely that the first gods were invented by people personifying forces of nature, such as lightning.

The oldest deity known to archaeologists and anthropologists is the Great Mother. Some people have speculated that she was worshipped during a time before humans had made the mental connection between sex and reproduction, and men thought that women simply gave life to new people.

In the same area of the world so that it would influence Judaism and the religions following it? Wikipedia has a decent article that mostly serves as links to the various pantheons. And another about the origin of Judaism specifically.

The long and short of it is that Yahweh has his origins on the Canaanite deity, El.