Avengers (1963) #248

"To Save the Eternals!"

The majority of Earth's Eternals form a Uni-Mind and decide to leave Earth to "find their destiny," taking the block made up of Deviants with them. Through unknown means, Ajak has separated from the Uni-Mind returned to Earth, but none of the other Eternals who are named as leaving (Valkin, Aginar and Zarin) have been mentioned or seen. In Eternals Volume 3 it was revealed that there were 100 Eternals on Earth. Presumably that means 100 remained or had returned between this point and the third Eternals series.