Go to www.anipike.com and look for the series you 
want; it's in alpha order.
Or just go to any search engine and type in the 
series you want. Jungle Emperor Leo (aka Kimba) is 
by Tezuka.  Another oldy is Matsumoto.  

Anime-cel.com has a nice personal gallery of oldy 
cels if you want to look at that.

It's really simple if you just do a little work.