Who supports ISIS?

Answer 1

It is suspected that Islamic State was originally funded by Saudi Arabia, several of the Gulf States, and Turkey. Of course, now all of these countries have been forced to withdraw that support because of the US pressure in leading its Islamic State bombing campaign. However, now, ISIL is basically self-funded. In 2014, ISIL captured billions of dollars in cash and equipment from the Iraqi Army (originally provided by the US) when they conquered Mosul and the surrounding areas. They also now control petroleum rich regions in the northern Iraq and are using the petroleum exports to bankroll any additional funds that they need. They are, by far, the most wealthy paramilitary/terrorist organization in the world.

There are, of course, conspiracy theories that state that Israel is supporting Islamic State that are grounded on the "evidence" that Israel is not attacking Islamic State and that Islamic State is not currently attacking Israel. By that logic, Israel is also funding Oman, Algeria, and Sudan, which is to say that without any coherent demonstration of Israeli monies going to Islamic State, this is just a conspiracy theory.

In terms of political support, ISIL is so toxic that practically no regime supports it.