Hi Andrew
I’m guild leader of Dark Wolves, a horde guild on the Connected realms of Lightbringer/Mazrigos and it sounds like potentially we might be what you’re looking for.
We’re a casual raiding/social guild established 2007, made up of adults 18+ although the majority are older - many with families and responsibilities irl, just looking for somewhere to chill online.
We raid Normal and Heroic raid levels only, currently working our way through Heroic. We’re definitely not the fastest or the best out there, but we do have fun.
We raid twice a week, Wednesday (21:00 ST) and Friday (21:30 ST). We also have a fairly active discord and plenty of people running various levels of M+.
We’re also made up of a bunch of altaholics and those who love collecting achievements, pets, mounts and just about anything else that can be collected 
If this sounds like it might interest you, please visit our realm forum post for more information: [H] Dark Wolves - 18+, Casual Normal/Heroic raiding, M+ & Social
Whatever you decide, and wherever you go, I wish you luck.