I think (he also sought forgiveness) for the children of the Ansar and the slaves and the freed men of the Ansar. I have no doubt about it.
Sahih Muslim Book 44, Hadith 245
← Previous Hadith O Allah,, grant forgiveness to the Ansar, the offspring of the Ansar and the offspring of the offspring of the Ansar. This hadith has been narrated on the authority of Shulba with the same chain of transmitters.

Sahih Muslim Book 44, Hadith 244 Next Hadith → O Allah, (bear witness) (and addressing the Ansar), said: You are dearest to me amongst people, (and said: O Allah (bear witness) (and addressing the Ansar), said: You are dearest to me amongst people. And he meant Ansar.

Sahih Muslim Book 44, Hadith 246