I changed my mind on Joltik. Its SR weak and is outclassed as a voltturn scarfer by magnemite, chinchou and larvesta. It's a D mon.
I nominate Shellos for D rank or possibly low C. Its very bulky and it has numerous utility moves in Scald, Clear Smog, Toxic and Yawn. It also has reliable recovery in Recover. Of course it is outclassed as a bulky water type by Frillish, Slowpoke and Chinchou. Staryu has less bulk but more offensive presence. It's actually quite a decent poke. Although the West forme is ugly as hell.
Also nominating Zigzagoon for D tier. Zigzagoon is the ultimate glass cannon. Kill or get killed. The standard Zigzagoon will try to set up Belly drum on a harmless poke and Extremespeed everything. It got 4 problems, Steel types, Ghost types, Fake out and difficulty to set up. Most players carry a fake out user and nearly all teams carry a Steel or a Ghost type which it cant beat due to lacking coverage.
You guys made me curious about Ekans. I got to check that out.