Here are the doffs listed by name so you can find them on the Exchange:

Very Rare

• Drolid

• Moulaysz

• Phemenne

• Phutpiel

• Strerant

• Tesva P'siv (purchaseable from Fleet Station K-13, but not on the Exchange)

Rare

• Peter Kenneth Daniels (purchaseable from Fleet Station K-13, but not on the Exchange)

Uncommon

• Mark Ford Jones (purchaseable from Fleet Station K-13, but not on the Exchange)

On the off chance you're looking for the KDF officers, here's the relevant wiki page.

Good luck!