i find chilling on inflatables with the waves relaxing so i would recommend an inflatable.

[water] bucket if you know the beach is known for fire pit gatherings. some people just bury their firepit in sand which tends to keep the sand warm longer than expected. water buckets are also nice if you want to find crabs hiding in sand.

vinegar, if the area is known for jellyfishes.

eyeglasses, mouth protection/ face mask if windy.