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
Heroes of The Storm