2013 through 2016 are remembered most for the Anderson KO and break that it started with and then the Bisping upset of Rockhold on short notice and Hendo gift title shot that it ended with.
I remember it most for the rankings being stacked with guys like Romero, Jacare, Mousasi, Machida, Whittaker and TRT Vitor though.
Anderson, Whittaker, Machida, Vitor, Rockhold, Weidman, Romero, Jacare, Mousasi, Bisping, Brunson, Hall, Munoz, Hendo, Leites etc… were all in the division.
Roger Gracie, Cung Lee, Gastelum, Diaz, Kennedy, Lombard etc… all had a fight in the division in this time period as well.
Five of the mentioned fighters are still top 15 MWs today.
Feel like overall, it was the best era of MW in UFC history and things just are not as interesting in the division at t he moment, not by a mile.