John Gill Commentary Genesis 30:11

"And Leah said, Fortunate! and she called his name Gad." — Genesis 30:11 (ASV)

And Leah said, a troop comes
A troop of children, having borne four herself, and now her maid another, and more she expected; or the commander of a troop comes, one that shall head an army and overcome his enemies; which agrees with the prophecy of Jacob, (Genesis 49:19) ; and she called his name Gad :
which signifies a "troop", glorying in the multitude of her children, that she had or hoped to have.