There are a lot of options depending on what you’re looking for.
Heavy Kaldorei themed RP guilds include
- Silver Circle (Religious/Adventuring Order)
[Archived] Silver Circle - Night Elf RP - #26 by Feyawen-wyrmrest-accord - Moonglaive Sentinels (WC 3 Military)
[A-RP] <Moonglaive Sentinels> - #110 by Moonwhisper-wyrmrest-accord
Medium RP guilds include
- Wings of Kalimdor (utd w/canon Military)
[A-RP] Wings of Kalimdor - Kaldorei RP Themed Guild - Keepers of the Moon (Cultural/militia)
[A-RP] <Keepers of the Moon> For Kalimdor! - Moonshroud Covenant (paramilitary)
They are all grand, and it will come down to whichever theme you prefer and what group you enjoy engaging with. To my knowledge, all of them welcome new players to their events to sample their RP.