This thread is a starting point, but you probably won't be able to compile a complete list of his cards with just this thread. I would recommend buying (or borrowing) someone's Beckett Alphabetical checklist book. That will list MOST (probably 99%) of Rube Waddell's cards.
You could also try
www.beckett.com to see what cards others are selling. Once at the website, go to Marketplace near the top and type in Rube Waddell. That is another option, but once again, won't give you the complete list.
I have four different modern Rube Waddell cards for sale on my website below.
http://www.bandkgreen.net/lefty_grove/cardsforsale.htm