Below is a list of 100 things to do at level 100 in World of Warcraft. Recently some players have made mention that there isn't much to do in WoW, so without further ado here is a list of 100 random things that came off of the top of my head that you can do at level 100. The list doesn't try to repeat itself too much (like list each seasonal event instead of saying "seasonal events") because it's supposed to give you ideas, not prove a point. There are some things that are similar to each other, but again we're trying to avoid fluffing the list out too much. 

Some activities are obscure, some are obvious, the list is all inclusive of various things to do in WoW both easy, medium, and hard. 

If you're ever sitting around trying to figure out just what to do in WoW, come consult this easy to use list to figure out your next great adventure in the World of Warcraft. 

1. Fight / farm reputation in Tol Barad.
2. Try out a roleplay server for a little while.
3. Get a Netherdrake.
4. Discover all of the scrolls in Pandaria.
5. Gank players in open world PvP.
6. Upgrade your gear through raiding / PvP / crafting / auction house.
7. Organize a low level raid group to take down Hogger like enemies.
8. Complete old dungeons & raids for achievements.
9. Do current level dungeons.
10. Level an alt to 100.
11. Get your garrison to tier 3 / fill your garrison full of buildings.
12. Hunt hidden treasures in Pandaria.
13. Complete all scenarios.
14. Complete old raids for transmog items.
15. Participate in Ashran.
16. Do the opposite of your daily routine, if you PvP then try PvE, if you PvE then try PvP - do what you least like.
17. Find a guild to join.
18. Level an alt specifically to be able to cut your own gems.
19. Complete Cataclysm quests achievements like "Ludicrous Speed" during the daily quests.
20. Have fun with the Brawler's Guild.
21. Complete Pandaria daily quests, and the associated achievements like "Test Drive."
22. Explore the world and try to explore all of every map.
23. Explore the capital cities and collect the various pets / mounts / toys available within each, including Dalaran.
24. Try to kill all of the Pandarian champions.
25. Rated battlegrounds.
26. Do your weekly garrison invasion.
27. To all the Squirrels... /love the various critters.
28. Analyze your gear and plan out your upgrades.
29. Try to attempt to reach silver or gold in the proving grounds.
30. Unrated battlegrounds.
31. Try to get all of the achievements for the Darkmoon Faire (and unlock all items).
32. Twink out an expansion level character (lvl 70/80/90) in full raid gear.
33. Farm gold through professions / auction house / gathering.
34. Do all there is to do with The Tillers.
35. Complete quests on the Timeless Isle.
36. Max out cooking / first-aid / archeology.
37. Try to attempt to reach silver or gold in any challenge mode.
38. Complete hard mode achievements in old school raids.
39. Kill the faction leaders.
40. Reach exalted with your guild.
41. Do the Ring of Blood, Amphitheater of Anguish and Crucible of Carnage events.
42. Do all of the Hemet Nesingwary questlines.
43. Fight all of the battle pet champions.
44. Earn various challenge cards in the Brawler's Guild.
45. Attempt to reach #1 in a statistic (kills / damage done / healing done) in a battleground.
46. Win the Highmaul Coliseum (accessed from a level 3 Gladiator's Sanctum).
47. Farm materials to craft epic items or novelty items.
48. Reach exotic locations in WoW and take screenshots of your character.
49. Visit the barber shop.
50. Fight a match in Wintergrasp.
51. Fishing for rare finds.
52. Gather materials for crafting.
53. Fight all of the different world bosses.
54. Discover all of the treasures in Dreanor.
55. Attempt speed runs of legacy content, record your times and upload videos on YouTube.
56. Grind reputations for various rewards.
57. Obtain various pet battle achievements, like raising various pets to level 25, on your way to become a battle master.
58. Level an alt to 19, 29, 39, etc. to do twink battlegrounds.
59. Farm honor through battlegrounds.
60. Make your main transmog set.
61. Collect vanity roleplay transmog sets.
62. Complete season events or prepare materials for seasonal events.
63. Learn to play the auction house.
64. Complete older legendary quests for cool transmogs now that they're soloable.
65. Try to obtain the "captain's treasure" in one of the chest brawl events (like at Darkmoon Faire).
66. Try playing the class you hate the most, it helps shake the game up.
67. Read all of the books in WoW, including the rare spawns in Dalaran.
68. Get a battle pet to max level.
69. Change your classes spec and try a new spec that you never tried before / haven't tried in awhile.
70. Do your Apexis Daily.
71. Hunt and collect Toys to fill your Toy collection.
72. Level alts for alchemy transmutes.
73. Collect various transmog hats so you have a new hat all the time.
74. Get a Nether-ray.
75. Make characters on the opposite faction and do the various quest lines / story quests to see the game from another perspective.
76. Farm bones on the Isle of Giants.
77. Arenas.
78. Farm/collection pets for your pet collection.
79. Do non-story related quests / backtrack to do quests you missed in Draenor.
80. Drink as many different beverages / eat as many different foods as you can (for achievements).
81. Do an LFR raid.
82. Do a fishing contest.
83. Farm all of the easy achievements (like explore maps, etc.) to help boost your achievement score.
84. Get to champion in the Trials of the Champion tournament in Northrend.
85. Clear out your mine / garden in your Garrison.
86. Get all of your daily quests done (and weekly quests too). You can also do daily quests in older content for rewards / rep!
87. Organize all of your loot on mule characters to make room in your bags.
88. Do current level raiding.
89. Farm gold.
90. Level up your bodyguards and your followers.
91. Capture rare hunter pets.
92. Get a Cloud Serpent.
93. Arrange for very low level duels (level 1-5).
94. Farm various titles.
95. Duel other players.
96. Farm quests in Azeroth for Loremaster.
97. Farm/collect mounts for your mount collection.
98. Try a UI replacement package or mess with the game's UI / addons.
99. Farm rares in Cataclysm, including in Thundermaw Ruins.
100. Try Heroes of the Storm! (Non-joking, make a cooking transmog set, with a chef's hat!)