The Lost Tribe of Gad is modern Spain and all other affiliated countries.
Jacob's pronouncement over Gad:
1 Genesis 49:19 19גָּ֖ד גְּד֣וּד יְגוּדֶ֑נּוּ וְה֖וּא יָגֻ֥ד עָקֵֽב׃ (WLC)
1 Genesis 49:19
1 Genesis 49:19 19Gad, a troop shall overcome him: but he shall overcome at the last.(KJV)
1 Genesis 49:19 19Gad, a troop shall overcome him: but he shall overcome at the last.(KJV/NC)
1 Genesis 49:19 19Gad, a troop shall press upon him;(ASV)
1 Genesis 49:19 19Gad shall go out to raid, and shall pursue at the heels of his enemies. (LAM)
1 Genesis 49:19 19Raiders shall raid Gad, but he shall raid at their heels. (RSV)
1 Genesis 49:19 19"Gad will be attacked by a band of raiders, but he will attack them at their heels. (NIV)
1 Genesis 49:19
19'Gad, a troop will press on him;
But he will press on their heel.(WEB)
1 Genesis 49:19
19'A troop will press on Gad,
but he will press on their heel.(WEB/HNV)
1 Genesis 49:19 19Gad will go out to raid, and will pursue at the heels of his enemies. (BRB)
The term raider would end up as the Spanish term conquistador and is best know as the Spanish gallions that raided Central and South American for what would be known as Spanish Gold.
Gad ended up with a considerable inheritance, including all of Central and South America.
The Treaty of Nijmegen forms the seal date document for Gad, and identifies Gad as Spain.
Curiously, on the exact seal date, a French fleet is sunk by Dutch ships in the Carribean, which is Gad's territory.