I will put this information into a table but for now here is a list of guild/clans in Blizzard games that I will update as I receive more information.

Official WoW Guild

Invictus - Alliance/Velen - Guild Lead: Xevrin

Unofficial WoW Guilds

Silverthorn - Horde/Gilneas - Guild Lead: Xevrin
Bloodline - Alliance/Greymane

Diablo III

Heroes of The Storm

Overwatch

Starcraft II

Destiny 2