An excellent resource for those interested in early Jewish interpretation of scripture is Alexander Samely's Midrashic Units in the Mishnah. The website is a companion to his fascinating work Rabbinic Interpretation of Scripture in the Mishnah (Oxford: Oxford University Press, 2002). Find it in a library here, or purchase it here.
The website has a database and accompanying resources for all of the examples of biblical interpretation in the Mishnah with the exception of Avot (which the author indicates will be added in the future). Samely has provided an English translation of each Midrashic unit and an analysis/commentary that uses the categories and terms he developed in his book.
You can search by tractate, biblical book, the code/category, the rabbi, formal features, or use a search term field.
This is a fantastic online resource for those interested in early scriptural interpretation and Rabbinic literature.
A good summary quote from chapter 2 of Samely's book:
"Mishnaic interpretations do not target the whole of Scripture, or any one of its larger parts, but rather segments approximately of sentence length. The hermeneutic licence to cut the text into small units which can be interpreted as if they stood alone creates a wide hermeneutic choice. Its fundamental effect is that the segment, taken in isolation, is less determined in topic, reference, or meaning than as part of a Scriptural environment (co-text). The Mishnah, in surrounding the segment with different co-text, can thus appoint a fresh topic, reference, or meaning for the biblical words" (31).