There are 14 tractates that were not canonized as part of the Mishnah...
There are 14 tractates that were not canonized as part of the Mishnah. Typically found at the end of Seder Nezikin, these are referred to as the “mesectos katanos” or “minor tractates.” A statement from one of the minor tractates is called a braisa rather than a mishna. The minor tractates are:
1. Avos d’Rabbi Natan – an expansion of the ethical concepts found in Avos; two versions are extant 2. Sofrim – laws of sacred books and the public reading of the Torah 3. Eival Rabbosi, AKA Semachos – laws of funerals and mourning 4. Kallah – sexual matters 5. Derech Eretz Rabbah – forbidden marital relationships, plus good manners and proper behavior 6. Derech Eretz Zuta – moral lessons for scholars and students 7. Perek HaShalom – statements on the importance of peace 8. Sefer Torah – laws of writing a Torah scroll 9. Mezuzah – laws of mezuzos 10. Tefillin – laws of tefillin 11. Tzitzis – laws of tzitzis 12. Avadim – indentured servitude 13. Geirim – the conversion process and the proper treatment of converts 14. Kusim – Samaritans (who were considered like Jews in some respects but like non-Jews in others)
Additionally, there is Talmudic discussion of tractate Kallah. The version of the braisos with this commentary is referred to as “Kallah Rabbosi.”