I work with MountainMage to handle matters related to signatures and artist proofs. Periodically, there will be signing events. You can follow them on Twitter or check the website for the latest updates.
MountainMage Twiiter: MountainMage, Signature Wizard ⛰️🧙🖊️ (@MountainMage) / X (twitter.com)
MountainMage Website: MountainMage MTG Signature Service (mountainmagesigs.com)