I made a "Hendo Moments" thread a few years ago... Some of the best gifs have vanished, but for reference, here's the post...
https://forums.sherdog.com/threads/dan-henderson-greatest-moment-career-appreciation-thread.3683015/
BRAZIL OPEN TOURNAMENT '97 CHAMPION (1997)
Wins 2 fights in one night on his debut, and wins the Lightweight tournament.
UFC 17 MIDDLEWEIGHT TOURNAMENT CHAMPION (1998)
Defeats Allan Goes and Carlos Newton to win the Middleweight Tournament. Has jaw broken vs Newton but fights on to win.
RINGS: KING OF KINGS 1999 OPEN WEIGHT TOURNAMENT CHAMPION (1999)
Defeats 2 guys in one night (Bakouri Gogitidze, Hiromito Kanehara), followed by 3 guys in one night; Lil Nog, Gilbert Yvel, and Babalu - all of whom had a big size advantage. Is crowned Open Weight Champion.
WINS PRIDE WELTERWEIGHT TOURNAMENT AND CHAMPIONSHIP (2005)
(couldn't find a decent pic or gif, so you'll have to settle for that - it's not from the tourny).
KO's Ryo Chonan, and Akihiro Gino on the same night, then beats Murilo Bustamante in the final to win the Tournament, and is Crowned PRIDE FC Welterweight Champion
WINS PRIDE MIDDLEWEIGHT (205LBS) CHAMPIONSHIP (2007)
Without giving up his 185 WW strap, Hendo moves up to 205 and brutally KOs Prime Wanderlei, and becomes the first person to simultaneously hold 2 belts at the same time in a major organisation.
UFC 100 - CREATES GIF OF THE CENTURY (2009)
After enduring months of trash talk from outspoken heel-allstar Michael Bisping on The Ultimate Fighter, Hendo delivered a KO that will live through the ages at the historical UFC 100 event. It was amazing.
WINS STRIKEFORCE LHW CHAMPIONSHIP (2011)
KOs Babalu in a title eliminator, then defendinf champ Feijao to win the 205 Strikeforce title - at the time Feijao was thought to be one of the better LHW in the world.
KNOCKS OUT FEDOR EMILIANENKO (2011)
Fighting at Heavyweight, Hendo moves up to face the apparent GOAT, Fedor Emilianenko - he was undersized, and coming in as a massive underdog - Hendo knocked him out for the first time in his career. Sherdog melted down.
Hendo Bless.
Honorable mentions go to beating Lombard aged 46, and having one of the fights of the last 10 years against Shogun aged 45 and getting the finish, knocking out Renzo Gracie, beating Ninja in Pride, His epic fight with Lil Nog, and hanging them up after a title shot which he arguably won.
Easy to forget how hard Dan Henderson actually is...