There are many rebel groups:
Syrian opposition - Wikipedia, the free encyclopedia
Fighting rebels number about 150,000. Many of which are local militias.
The salafists are mainly in Al Nusra and number 6-7 thousand.
However they weren't extreme enough for many and there was a rift.
The jihadist nutters left to for ISIS, which conducts most of the ethnic cleansing type atrocities. They want to create a Sunni Caliphate.
Because the nutters left Al Nusra it became a lot more moderate and became more friendly with the FSA. Against whom it had sometimes been skirmishing.
ISIS will fight anyone who doesn't support their world view.
Then there is YPG in the north trying to create a de facto Kurdish enclave, which the Turks don't want.
There has been a lot of fighting between the YPG and the jihadists. Today the YPG won three villages back.
The ultimate resource for on the ground news (and propaganda) is:
https://twitter.com/PicoBee/syria-en...g-rpts/members
Good explanatory diagram:
https://pbs.twimg.com/media/BTbdKHVCUAEOwG0.jpg:large