Square Enix will be releasing a special Kingdom Hearts themed silicone ice tray featuring various iconic symbols from the series! This will release in Japan in September 2018.
You can check below for further images:
UPDATE [June 30, 2018]: The ice tray is now available for pre-order on the Square Enix North America Store. The tray will cost $13.99 but has a pre-order price of $12.59 and will release in September 2018.
Thanks to @churroz for the tip!