I speak only in terms of decoration:
it would be nice to have new marine elements. Right now I’m thinking of luminous starfish in all colors.
They would be a very good ornamental element. For its applications in terms of the resource they offer and its use, I give the floor to neards ^^
We can make a combo with seashells which will be just shiny.
Coral + Starfish + Seashell 
I take everything !!! I am not asking the developers to redesign the seabed but to bring some fun elements that can be used for decoration and beautify our oceans. -
Coral and shell blocks could possibly become the next classy building material
Coral = porous and matt block
Shell = ridged and shiny block
What if there were also Refined Shell blocks, like they had a pearly iridescence?
Ooooh yeeees -
