There are nine achievements that are awarded for reaching certain honorable kill milestones in the game, each worth 10 achievement points. In ascending order, they are: "An Honorable Kill," "100 Honorable Kills," "500 Honorable Kills," "1,000 Honorable Kills," "5,000 Honorable Kills," "10,000 Honorable Kills," "25,000 Honorable Kills," and "50,000 Honorable Kills." Players who earn the final kill total achievement, "100,000 Honorable Kills," also receive the "of the Horde" or "of the Alliance" title.
Earn the "Duel-icious" achievement by winning a duel against another player. It's worth 10 points. The "That Takes Class" achievement is worth 10 points and is awarded for getting a killing blow on one player from each of the game's classes. The 10 point achievement "Know Thy Enemy" is earned by getting a killing blow on five different enemy races. The "Make Love, Not Warcraft" achievement (a reference to the famous South Park episode of the same name) can be earned by performing the /hug emote on a dead enemy player before they are able to release their corpse.
Loot the [Arena Master] trinket from the Gurubashi Arena in Stranglethorn Vale to earn the "Gurubashi Arena Master" achievement and 10 points. Get the "Gurubashi Arena Grand Master" achievement, along with 10 points, for completing the quest given by Short John Mithril to earn the [Arena Grand Master] trinket.
The 10 point achievement "Freedom of the Alliance" is awarded to Alliance players who obtain an Insignia or Medallion of the Alliance. On the Horde side, "Freedom of the Horde" is earned for obtaining an Insignia or Medallion of the Horde. It's also worth 10 points.
Get the "Call in the Cavalry" achievement, and 10 points, for earning any of the War Mounts available through the Honor system.