Supposedly, we have cross-faction cross-server guilds now… Ok, so how do I find one of these? I got randomly invited to some spam guild called H E R O, completely dead chat with 16 people online… There’s no guild finder since the one we have doesn’t work still. I can’t /who people from other servers… How do I find an active PVE guild? 
Guildsofwow google it
Okay I found the site. Thanks for that info. But how do I know which realms work with mine cross server??
Try putting “the war within” in the search bar for keywords in guild finder… some active guilds update the recruitment page showing they are active.
Any realm should be fine