In particular, between 2014 and 2016, it was possible for dedicated players to generate quantities of gold that were previously impossible to obtain, and have not been possible to obtain since. The Warlords of Draenor expansion was the first time the game included nonplayer character followers that players could send on missions to collect resources, items and other useful stuff, including gold.
Congratulations on reaching Level 120! There are a myriad of new things to do. The first thing you should do is head to your faction hub ship where you have been doing your mission table quests and footholds to pick up and complete the quests necessary to unlock World Quests. World Quests will provide you an opportunity to grind reputation levels, acquire gear, and gather Azerite. There are tons of new things to do that we will cover in our Level 120 Battle Guide found here: Level 120 Battle Guide