Starting April 1, for just one referral, you can get your very own mount skin! The Alpaca skin turns your Stag base mount into a charming, loyal companion - and once you've unlocked it, it can be used by all characters on your account forever.
On top of that, as with the last season you can earn huge amounts of Fame for your third and fifth referrals: three referrals scores you a T7 Pile of Tomes, worth a whopping 100,000 Fame, and five referrals gets you a T8 Pile of Tomes, granting a colossal 200,000 Fame. And as always, your first-ever referral grants an additional T8 Pile of Tomes along with the Alpaca mount skin.
The current referral season lasts until maintenance on June 1, so you've got until then to refer your friends and claim your rewards.