Claws Mail is a cross platform e-mail client based on GTK+.
Ranked in these QuestionsQuestion Ranking
Pro Low resource client
Claws Mail is a low resource e-mail client that is often default in low resource Linux distributions.
Pro Clean interface with 5 layout variants
Pro Has many plugins for extra functionality.
Pro Good support for Google's services
Con Interface looks old and setup is not easy
The icons as well as the rest of the interface look like an application from the early 90's, with this there is also no easy setup options built in like the more modern e-mail clients.