Abba and others; it is arranged according to the Mishnic orders and tractates, but lacks IV.
2
Both Talmuds are arranged according to the six orders of the Mishnah, but the discussion of the Mishnic text often wanders off into widely different topics.
3
Mishnah, but they differ from and are sometimes older than the Mishnic material, with which they sometimes conflict (so in particular as regards the rejected decisions of the school of Shammai).
4
What is practically Mishnic Hebrew continued to be used in Midrash for some centuries.