Here are some that come to mind off the top of 
my head:
 
 WebDeb's Gallery: www.jersey.net/~dnilsen/cels/
 
 The Fruity Allen Lover's Gallery: 
www.lizzard.net/Cels (Home of Sock Ally!!)

 Say's Gallery:
http://members.jcom.home.ne.jp/goku-sai/goku-sai-
hall.htm

 Morgan's Escaflowne gallery at Rubberslug:
 (which seems to be down at the moment?)

 Deb has a bunch of Escaflowne cel galleries 
listed on her links page which can take you to 
even more places. Hope this helped!