Early
-Men and bow equipped version of samurai ( katana, nodachi, naginata, bow, yari, cav).
-Levy troops aka conscripted farmer.
-Samurai Retainers recruitable in clan specific buildings
Middle and late
-Women troops, of course. Unlocked through technologies.
-36 hero units, recruit in clan specific buildings with some history figure.
Some addiational to unit roster
-Yoshiwara's Guardian
-Noel cavalry
-Shinsengumi
-Sisters
-Tetsubo Warrior
-Light Saber
-Late Ashigaru
-Wooden Canon
-Ikko Ikki version of great guard and light cav.
-Naked Fanatic
-Kyokai's Unit
-Tay Son foot soldier
-The Valkyrie
-Land version of the Valkyria
-Elf's archer
-Ametris line infantry
-Naginata Cavalry
You now can't recruit any hero units in the campaign any more, except for the one in clan specific buildings. There are 35 of them to get. =) Gotta catch them all.
Matchlock samurai was removed from the campaign since the teppo was the weapon of no honor.