#2. The New Day - Longest Tag Team Championship reign

The New Day have now been together for over five years, making them the longest-tenured faction in WWE history. As of this writing, The New Day are 8-time Tag Team Champions, having won the RAW and SmackDown versions of the title 2 and 6 times respectively.
The most notable reign in their run, however, was between August 2015 and December 2016, where they would break the record and become the longest-reigning tag team champions in WWE history.
The record was previously held by the legendary Demolition, who held the titles for 478 days. The reason why Vince McMahon went out of his way to have The New Day break the record was that Demolition's Ax and Smash were a part of a joint lawsuit accusing WWE of being responsible for head injuries caused during their tenure with the company.
They would lose that lawsuit and The New Day ended up making WWE history before promptly dropping the titles to Cesaro and Sheamus 4 days after setting the record.