Leo’nnyr’s Honor Guide for Horde Expedition
For this guide I have gone to every dungeon in Northrend to figure out the potential amounts of reputation that can be earned with the Horde Expedition, any Rep gained with them will also count towards reputation with The Sunreavers, The Taunka, The Hand of Vengeance, and The Warsong Offensive. There are a few dungeons in Northrend that are not worth the effort/time it takes to complete them like Ahn’Kahet: The Old Kingdom and Azjol-Nerub, That being said if you do wish to do these dungeons you will still get reputation with The Sunreavers. I created this guide specifically for The Sunreavers to obtain the tabard but it can be applied to any or all of the factions included. There are also things like the Argent Tournament in Icecrown that will give daily quests that will give you some rep with The Sunreavers but as it is only around 750 per day i’m not sure i would consider it time/cost effective when compared to dungeons (plus no one wants to kiss frogs :P) but keep in mind that to get The Sunreavers Tabard you need 50 champions seals so you will have to progress through the Argent tournament to some extent. Now for reference i did all of these dungeons at level 60 with over 220 Ilvl gear during the Shadowlands Expansion -With no faction tabard on-, im sure you could solo this at earlier levels but seeing as most of the enemies are 30 elites i wouldn’t recommend doing it if you can’t one-shot every enemy since it will take you that much longer. -The amount of reputation you receive will vary to the numbers i have listed here- I can’t say for sure that i killed every enemy and i know in The Nexus there was one boss i didn’t know how to get to. So with all that out of the way here is the guide, hope this helps you all! 
Start by heading Dalaran in Crystalsong forest, then fly to
-Zul’Drak-
Gundrak (Heroic) – 1,408 Rep
Drak’tharon Keep (Heroic) – 1,296 Rep
Then fly down to
-Howling Fjord-
Step one Utgarde Pinnacle (Heroic) – 1,367 Rep
Step Two, Utgarde Keep (Heroic) – 1,367 Rep
-Hearth to Dalaran-
-Borean Tundra-
(do these two in any order)
The Oculus (Heroic) – 1,119 Rep
The Nexus (Heroic) – 1,570 Rep
-Hearth to Dalaran-
-Icecrown-
Make sure to grab the start of the quest chain inside The Forge of Souls
Step one The Forge of Souls (Heroic) - 737 Rep
Once you get into Pit of Saron you can stop doing the quest, Halls of reflection gives very little rep and takes a long time.
Step two Pit of Saron (Heroic) – 1,287 Rep
-Hearth to Dalaran-
-Storm Peaks-
Hall of Stone (Heroic) 2,391 Rep
The dungeons that are not worth it time/cost wise or don’t give rep with all of The Horde Expedition are:
Ahn’kahet: The Old Kingdom
Azjol-Nerub
Halls of Lightning
The Violet Hold
Trial of the Champion
Halls of Reflection
Now there are a few of these dungeons that when I killed the enemies it said i was gaining reputation with The Taunka instead of The Horde Expedition, but after checking you do still get rep with the rest of the other factions.
All in all I ended up getting around 11,500 rep with The Sunreavers, The Taunka, The Hand of Vengeance and The Warsong Offensive. Somewhere along the line I became exalted with The Horde Expedition? So I guess you get more rep with them than the bleed over to the sub category factions included in it.
Most of the dungeons on this list I tried resetting instances to speed farm them, but they are stuck on the daily reset. So all in all going from Neutral reputation to Exalted using this guide should take (around) 4 daily resets.
Thanks for reading my guide! I really hope this helped, and want to state that I am by no means an expert in this kind of thing so some of this info might be off. These are just the findings that I got in my own time spent in the game. If you find any errors or have any comments, criticisms or questions feel free to comment. Thanks again! And good luck out there