Adventure Island at Busch Gardens in Tampa FL offers a Preschool Card. It grants children ages 5 and younger complimentary admission to the park through the end of the 2020 season.
Online registration is mandatory and the offer is for Florida residents only. After checkout, parents receive an email containing a PDF version of the Preschool Card to use for admission.
Guests may have to show valid form of ID to verify age prior to entry. More details are here.