The New Yorker has a short overview[1]. The ACLU has a more complete list[2]. The American Prospect and Cato Institute have some articles if you search around, but I'm not a huge fan of their work.

1: https://www.newyorker.com/news/daily-comment/obama-leaves-tr... 2: https://www.aclu.org/news/free-speech/leak-prosecutions-obam...