Hi there!
If you’re a discord user, I recommend checking out the Wyrmrest Community Project: Wyrmrest Community Project - Wyrmrest Accord - World of Warcraft Forums (blizzard.com)
it’s an active spot to make RP connections, get a feel for what’s out there in the wide world of Wyrmrest, and they have a guild listings directory you can browse in addition to the forums here. 
I originally started RPing on Earthen Ring and I can say that since I’ve found my way on Wyrmrest over the last few years, finding a guild (or discord community) really opens up the experience on this server.
May I also recommend the guild I am part of, the Violet Vanguard? We’re not orc-focused, but a cross-faction band of characters focused on world RP storylines, with multiple DMs to hit a variety of themes and activities week-to-week. We have active weekly guild RP sessions every Thursday at 5PM server / 8PM EST. We coordinate a lot on discord and in general ours is a welcoming, easy-going roster of players interested in PvE and RP. Here’s our forum post: [H/A RP-PVE] Violet Vanguard Recruiting for Dragonflight!
Oh! Also, if you want to stick to Moon Guard and play orc, I do know of a guild called The War Wolves on Moon Guard who are part of organizing seasonal Kosh’arg RP events with the great orc community: ⫷- [H-RP] - Military RP Guild -⫸ - Moon Guard - World of Warcraft Forums (blizzard.com)
Either way I hope you can find the right guild for you!