Snakes are typically green creatures, but show also other colors, as the black swamp-snakes. In humid territories they can be really slippery. They have usally one of either ways of attack: venom and constriction.
In Kamigawa lives a sentient race of Snakes, the Orochi. They are not limbless and live in the forests. They are skilled hunters and use a stunning poison.
The Yuan-ti from Faerun