Phylopic.org, owned and maintained by T. Michael Keesey, is an amazing website whose goal is to accumulate as many reusable silhouette images as possible of every organism on planet Earth. These images can be submitted by anyone and are free for anyone to use on presentations, projects, and artworks with appropriate credit.
But the really cool thing about Phylopic is its phylogenetic database. Its Python-based framework stores accurate phylogenetic data for every organism, so you can view a full phylogeny for any organism as many levels back as you want. As long as images are available for the taxa you’re searching, this can result in beautiful evolutionary sequences like the one above showing the evolution of Homo sapiens.
This project is incredibly useful to researchers, students, artists and laymen alike, and needs to be supported! The creator is now selling this gorgeous t-shirt (definitely the most accurate “evolutionary sequence” t-shirt available anywhere) in order to cover costs of web hosting. Please considering purchasing one or spread the word!