The dataset for the Fractionalization article cited below can be downloaded in Excel format from Romain Wacziarg’s web site (scroll down the page — it’s listed under the journal articles).
Alesina, Alberto et. al. “Fractionalization.” Journal of Economic Growth, vol. 8, no. 2, June 2003, pp. 155-194.
What: measures of ethnic, linguistic, and religious fractionalization for 190 countries.