• Wheat
  makes soldier never attack, even if hit first
• Nether Wart
  makes soldier attack its allies
• Fermented Spider Eye
  makes soldier not attack, unless attacked first
• Rotten Flesh
  makes soldier attack hostile mobs, if infected soldier will also attack friendly/passive mobs and players
• Sponge
  makes soldier not attack, not be attacked (except by zombie/netherwart soldiers), and use healing items on any soldier rather than just own team

What about the Ender Pearl?

Ender pearl (Corrupts a clay soldier to attack others to corrupt them and will attack you, hard to kill with diamonds, best if you avoid giving super soldiers ender pearls)

From Clay Soldiers Gamepedia

Unless that's what the Rotten Flesh will basically be.

Ender pearls are listed here:
#203

We moved some stuff around for the future.
Basically soldiers will only attack all other soldiers when infected with a pearl.
Rotten flesh makes them attack hostile mobs only when "normal" and also players / passive mobs when infected

Ah there it is, must have skipped over it when I was looking at that list earlier, my bad!