1) D-Generation X - WWE
WWE's direct answer to the NWO was D-Generation X. The New World Order was formed on the backs of former Kliq members Scott Hall and Kevin Nash. The two men made the jump from WWE to WCW and created a legendary group that truly revolutionized the business. Before leaving the WWE, they said goodbye to their fellow Kilq members Shawn Michaels and Triple H with the infamous Curtain Call.
The remaining Kliq members were separated in WWE for quite a while after their departure, but 1997 saw a lot of things change in the company. The NWO were riding high in WCW, so Vince McMahon took more chances with the characters and allowed performers to take risks.
Shawn Michaels started to show more of his real-life personality and officially turned heel at SummerSlam 1997 when an irate chair shot to The Undertaker cost him the WWE Championship to both men's rival Bret "The Hitman" Hart. During his feud with The Undertaker, Michaels teamed up with Hunter Hearst Helmsley in a tag match against Taker and Mankind.
The two men brutally attacked Taker after the match and created a bond against The Deadman. Triple H and Chyna were soon closely associated with Shawn Michaels and his insurance policy Rick Rude from there. In October of 1997, Michaels officially dubbed the group D-Generation X in a promo exchange with Bret Hart.
DX were at the center of the most infamous moment in WWE history with the Montreal Screwjob at Survivor Series 1997 against Bret Hart where HBK defeated his rival to win the WWE Championship after Vince McMahon called for the bell. With DX now on top of WWE, the company named their next pay-per-view after the stable, marking a first in the promotion's history.
To add even more star power to the faction, Iron Mike Tyson joined D-Generation X in the lead-up to WrestleMania 14 after his hostilities with Stone Cold Steve Austin. Austin defeated Michaels to win the WWE Championship at the Showcase of Immortals with Tyson turning on HBK afterwards in what would be Shawn's final match for four years.
D-Generation X didn't slow down there though. The next night, Triple H officially kicked Michaels to the curb and welcomed the returning X-Pac into the stable. To end the show, DX helped the New Age Outlaws win back the WWE Tag Team Championships and officially welcomed Billy Gunn and Road Dogg to the group as well.
This was DX's most memorable lineup. Triple H, X-Pac, Road Dogg, Billy Gunn and Chyna became wildly popular thanks to the charisma, outlandishness and stunts like the famed "invasion" of WCW. They also took part in a fondly remembered rivalry with The Nation that saw Triple H beat The Rock to win the Intercontinental Championship in a Ladder Match at SummerSlam 1998.
Triple H would betray DX at WrestleMania 15 and join the Corporation, but they would later reunite after The Game became WWE Champion in late 1999. Regardless of what iteration, DX were at the center of some of the biggest moments in company history. That's why D-Generation X is the best stable of WWE's Attitude Era.