I have a couple of official mats, plus a sea mat which is a vynal type table cover, plus a light cloth mat from Tinywargames.
I quite like the Tiny mat, but must admit to wanting one of the mouse mat type sea mats from Deepcut studios when I next get to a show

https://www.tinywargames.co.uk/sea

https://www.deepcutstudio.com/produc...caribbean-sea/

Well thats my dream anyway