Today is a great day.
ALL, every single Unique and Super-Unique monster in Diablo III and Reaper of Souls received as much info as available.
531 total monster. I am frightened to think how long it has been...
Anyway, we are the best Diablo wiki in the world, and are one step closer to staying that way forever.
Regarding the said monsters: there is never a release. Some of them did not get screenshots. Some got screenshots, but did not receive extra info. Some are so rare that nobody even knows what type of monsters they are.
Want to help? Take a look at the list below, and if you see those bastards, before you kill them, take a second and write down what it was all about :P
Details and / or Screenshots of Unique monsters: Snoglatch Grimwield (Highlands Crossing), Grool (Eastern Channel), Jonathan Muddlemore, Pontius (Westmarch Commons), Gozmol (Paths of the Drowned), Yellow Ledbiter (Briarthorn Cemetery), Fearby the Prowler, Trejiak (Westmarch Heights), Mekhare (Perilous Cave 1), Marko (Mass Grave), Templeton (Plague Tunnels Level 1), Pontius (Westmarch Commons), Rolph Duke, Mort Duke (The Vault)