Astral Plane

The Astral Plane is a mysterious plane of existence that is (relatively) easy to get to but very difficult to leave. The Astral Plane is an open void with a fuzzy static sky of grey light with the occasional floating rock island. Generally time does not exist in the Astral Plane. Here time is like an ocean, when its calm time does not flow but when its turbulent time will progress forward. Many different things can cause time to flow here such as, beings accidentally entering the plane, large magical events, significant magical events in other planes and far off time ripples propagating.
Unless there is a disturbance time does not pass in the astral plane. The body of someone from the material plane will maintain their magical abilities for a while here but eventually the memory of flowing time will fade and take their power from them, time flowing again restores this. While time is calm (or too long has passed since entering the astral plane), you do not age, require food or grow hungry, wounds do not heal but you will also feel no pain or die. If time begins to flow again there is the possibility for dire consequences.
The Gith live in the astral plane as well as other creatures. These beings do bot require time to flow to use magic. The Gith move around on large floating ships powered by boiling refined time crystals and using it in a way akin to rudimentary steam tech. Some floating islands have colonies of exiled Gith and other beings from other planes of existance that have become trapped here.
It is possible to harvest time crystals, known as Chrononullite, that float in the astral plane, these can be used to move around.