Is there a place where we can view all of Ziggs' drawings for alternate game modes?

Try the pages for each of the modes on the wiki.

http://leagueoflegends.wikia.com/wiki/Category:Ziggs

Fun note, all those featured game mode pictures were inspired by Zigges original teaser picture. http://img1.wikia.nocookie.net/__cb20120125030651/leagueoflegends/images/a/af/Sneakpeek_Ziggs.jpg