John Gill Commentary Numbers 26:15

"The sons of Gad after their families: of Zephon, the family of the Zephonites; of Haggi, the family of the Haggites; of Shuni, the family of the Shunites;" — Numbers 26:15 (ASV)

Ver. 15-18.

The children of Gad, after their families tribe was numbered next to Simeon because it lay encamped with that under the standard of Reuben. There is a little variation in the names of two or three of his sons, from those by which they are called (Genesis 46:16) , instead of Ziphion, here Zephon; and for Haggai, here Haggi; and what is much wider, for Ezbon, here Ozni. Seven families sprang from Gad, whose number now was 40,500; they were diminished since their last numbering 5150; it is probable this tribe, being a warlike tribe, suffered very much in their attempt to enter the land of Canaan contrary to the will of God, and were repulsed and defeated by the Amalekites, (Numbers 16:40–45) .