Er... where to start.
I believe Saurfang is a NPC that used to be stationed in Orgrimmar and is famous for his incredibly strong Cleaves and
Saurfang's Rage where the damage doesn't get mitigated by armor and such even though it's a melee attack. Before he was moved to Warsong Hold in Northrend, he is the main reason why Orgrimmar raids always come through the side entrance and not main. The memetic status of Saurfang came from the big speech he made at the AQ battle, where he basically told the world they'll win 'cuz he's Saurfang. As a result, people started making Chuck Norris like jokes about Saurfang.
Mankrik's wife on the other hand is an infamous icon from the
Barrens Chat. Since she was relatively hard to locate for a newbie that first started and led to The Barrens, one would often see "Where is Mankrik's wife?" on the general chat that it got so annoying to the other players and I guess it just picked up from there. Her death is often linked to Saurfang due to his "uberness" and Mankrik's wife being labeled as "Beaten Corpse" in game.
Spoiler for the speech he gave at AQ:
Link to a video where I believe Saurfang took down a 40 man Alliance raid without Horde players intervening.
Note: Contrary to OLD CN/VD jokes, most of them are actually quite funny and of course, WoW related.