The website Sefaria is an extremely rich collection of resources regarding Rabbinic literature. From their own website: "Sefaria is home to 3,000 years of Jewish texts. We are a nonprofit organization offering free access to texts, translations, and commentaries so that everyone can participate in the ongoing process of studying, interpreting, and creating Torah."
Jewish Interpretation of the Bible by 
Introduction to Rabbinic Literature by 
Scripture and Tradition by 
The More Torah, the More Life by 
The Oxford Annotated Mishnah by 
A Scripture Index to Rabbinic Literature by 
The Targums: A Critical Introduction by 
The Targums by 