Sky Series Collection
 A collection of 87 hdr skies all in 4k resolution.
Take advantage of hdri's High Dynamic Range for you reflections and lighting in a way you can't with just regular jpgs or pngs.  
 
*Now Six-Sided optionality for Daylight, Sundown, and MidNight. Great for mobile.
Choose from a selection of 8 different themes for the skybox that fits your need.  
Daylight 
Sundown 
Sunless 
Skyhigh 
MidNight 
Planetary
Unearthly
And Apocalyptic
*Ex update 1 added 5 more hdri
*Ex update 2 added 4 more to extras 
*Ex update 3 added 5 more, one to each: Daylight, Sundown, Skyhigh, MidNight, Plaentary.  
*Ex update 4 adds 6 more Hdri to the collection
*six-sided maps are 1024x1024 per side
*It should be noted that unity requires all equilateral cubemaps (the hdrs) to be processed on import. This means a longer import time is to be expected. if your running on a lower spec machine it's recommended that you import the ones you need first instead of all at once.