Lileep and Cradily are mentioned in many dex entries saying that they live in the sea and they are both rock-grass type. Also Crabrawler and Crabominable are both crabs so they could be oceanic (Crabrawler is fighting and Crabominable is fighting-ice. Clobbopus and Grapploct are octopuses (the correct plural of octopus) both only fighting type. Pincurchin is the Sea Urchin Pokemon and is only electric type. Eiscue is a penguin so maybe oceanic (it's ice type). Dhelmise is the Sea Creeper Pokemon and is an anchor and it's ghost-grass type. Dragalge is the Mock Kelp Pokemon and loses it's water type when it evolves from Skrelp (it's Poison-Dragon type). Dratini and Dragonair are both only dragon type and they live in the water. Dwebble and Crustle are based off crustaceans (both bug-rock type). Tynamo, Eelektrik, and Eelektross live in the water and are based off fish and are all electric type. Inkay and Malamar are based on squids (which live in the ocean) and are both dark-psychic. Vanillite, Vanillish, and Vanilluxe are based on ice cream which has salt in it and you could use sea salt which comes from the sea and they are all ice type.