A lot of the books are specialized (as in per country). For United States Tokens, there's
A Guide Book of Tokens and Medals (Bowers Series) (
Amazon http://www.amazon.com/Guide-Book-To...54173&sr=1-2 ). I am not sure of the years, but I have it somewhere and will check. If you're looking for Great Britain,
British tokens and their values; (Seaby's numismatic publications) was published in 1970 and could contain post 1900.
Canadian Colonial Tokens by W. K. Cross and
Coins, Medals and Tokens of the Philippines 1728 - 1974 by Aldo P. Basso were a couple more I found.
Also, you could try Unusual World Coins by Krause. It contains everything from micro-nations to fantasy coins, but has other items not covered by the regular Krause catalogs such as tokens and such. I think the current version has 1994 and prior. Actually let me double check that one, too, as I'm not 100% sure that's where I saw a few tokens I looked up.