The best replacement for quests is dungeons.

The best alternatives to quests are rated as following:
★★★★★  dungeons
★★★★  dungeons leveling
★★★  grinding
★★  dungeons wow
★★  instances
★  instances leveling
★  dungeon
★  skyrim quests
★  random dungeon

Your alternative for quests is not listed? Suggest!
Speaking about quests, one probably shouldn't forget about dungeons.

Other search terms related to quests and their ratings are:
★★★★★ dungeons
★★★★★ darnassus rep
★ darkspear rep
argent crusade rep
You have in mind a companion for quests and it is not yet here? Propose!



Google Trends

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quests
dungeons
dungeons leveling