Hey there Mirthos, I was wondering if you needed any help?
I have already been working on a Drowned design (I am not that good at making new textures though)
And also wondered if you would be interested in my Shulker Design if you decide to change. My works more on the premise of them trying to blend in.
I will Edit this later to include Screenshots.
Edit: Added Screenies (though for some reason transparency apparently does not work on the Drowned models...)
And a Link for them: http://www.mediafire.com/file/xfc3xluqufp1d6e/1.13_WIP.zip/file