Sprite URLs FTW

http://rpg-home.lunar-net.com/choose.htm
Animated GIFs and illustrated walkthroughs for the Phantasy Star, Shining Force, and Lunar series.

http://www.roempire.com/database/?page=monsters&act=list
EVERY monster on Ragnarok online, including thier walking, attacking, and death animations.

http://dbz.icequake.net/share/afs/pub/emu/nesnew/www.theredeye.net/index.html
TheRedEye's site, brought back from the brink of infinity. Not sprite-related, but that's OK.

http://hkaityo.hp.infoseek.co.jp/dq/index.html
Japanese page with a buttload of monster pictures from the Famicom and Super Famicom Megami Tensei games, as well as ones from Romancing SaGa 1,2, and 3.

http://www.pekori.jp/~emonoya/monster/index.html
An impressive collection of monster images from Wizardry installments across various platforms. Oh yeah, and it's in Japanese.

http://yois.if-legends.org/
Ye Olde Infocomme Shoppe. Peek inside the Vault to see covers for lots of text-based games. Not sprites, but I like 'em, OK?

http://sdb.drshnaps.com/
The only sprite database I know of that has a plentiful amount of DS sprites.

http://www.odinsrealm.com/tatakau/
Sprites from mostly obscure games.

http://www.bogleech.com/games.html
Scythemantis's fabulous collection!

http://www.vgmuseum.com/mrp/castle.html
Mr. P's Castlevania Realm.

-NULL-
Final Fantasy boss sprites compared across different platforms. (not working at the moment)

http://www.woodus.com/den/home.php
Dragon's Den.

...and that's it.