Hasbro has sent out notifications to Hasbro Pulse Premium Members to reserve a spot in line for their booth at SDCC in order to purchase exclusives. First come, first served.
All reservations requests are due by Monday June 24, 2019 at 9:00 AM EST.
Thanks to YogiKai for the heads up.
UPDATE: Reservations are now full and the page removed.
UPDATE 2: New link added.