Al Nusra has just wiped out Nour al Dein al Zenki in a matter of days. Zenki were a faction backed by 6 different countries, including UK & US & were touted as "moderate rebels" until they were exposed. [link]
The 2 major factions left in Idlib are: Al Nusra & National Liberation Front.
Al Nusra (aka Hayat Tahrir al Sham (HTS), aka al Qaeda in Syria) are a splinter of ISIS & the group Israel is most closely aligned with, having supplied humanitarian & military support for the group for years when they were situated on the border of the occupied Golan Heights.
National Liberation Front, a splinter of the "Free Syrian Army" group supported by Obama are now backed mostly by Turkey.
Click to expand map...
- note: the 'Turkestan Islamic Party' - these are Uyghurs from China, smuggled into Syria by the Turks.