Dartmouth are mostly famous for their Gluggle fish jugs. The queen took a liking to them. You'll probably see them a lot in pubs as they sometimes have Plymouth Gin wrote on them. Glug jugs came in different sizes and colours and were produced by different manufacturers over the years. Including, i think, Thomas Forester and Foster pottery. They all make that glug glug noise when water is poured out of them, hence the name. Common colours are brown and green, although you may see rare shades in those colours too.
This very small one below is unusual i think, it's kind of grey with a light blue tint to it. It's marked Dartmouth on the base.