As some of you know, I run the website spawnworld.com , in which I try to catalog every Spawn comic in the world (including the main series, mini-series, crossovers, cover appearances, etc..).
In doing so, I also write a Spawn encyclopedia, which includes every proper-noun ever uttered in the comics. (currently there are only 20-30 entries that I have not written yet, out of over 1500).
To celebrate the upcoming release of Spawn 300, I've used the encyclopedia to put together a poster featuring every character that has ever been pictured in the comics - all 1362 of them!
Feel free to check out the poster, download it if you choose (it's free!), and peruse the site. You'll find links for the poster as the top item on the homepage.
Enjoy!