Important quests that either give access, or reward something that you likely want/need for progression.
ROS Important Quests
Panda 2021 Timeline - set of 4 white adorns that gives +19 fervor overcap and +21 fervor with all 4 equipped.
Vah Shir Racial Timeline - cats are cool
BOL Important Quests
Sol Eye Heroic Timeline - gives fires of mystery blue adorn with +80 Fervor, +40 Fervor Overcap)
Panda 2020 Timeline - set of 4 white adorns that gives fervor overcap and fervor with all 4 equipped.
Diaku Corral Quest Timeline - Multiple mount gear rewards. Solo or Heroic versions give updates.
CD Important Quests
Celestial Doctrine - At least once, so you can get your Level 10 Ascension stance leveled up to to Celestial (adds 10 ability doublecast).
Blue Mystery Runes
-  Shadow Touched Rune: Mystery (+100 Fervor, +60 Fervor Overcap) - ?
-  Fires of Mystery Rune (+80 Fervor, +40 Fervor Overcap) - Reward from the Achievement "Triumph: Answer the Call" , Defeat all bosses within Solusek's Eye: The Calling [Heroic]
-  Vindicator's Rune of Greater Mysteries (+80 Fervor) - From defeating Soren the Vindicator in Fabled Kael Drakkel.
Blue Embers Runes
-  Shadow Touched Rune: Embers (+50 Fervor) - ?
-  Embers of War (+35 Fervor) - Reward from the Achievement "Perfect Raid: The Fabled Flames of War" in Fabled Plane of War . Defeat all bosses flawlessly within The Fabled Plane of War [Raid]
-  Celestial Rune of Embers (+25 Fervor) - Reward from the Achievement "Triumph: Unmeltable!" Defeat all raid encounters within Doomfire: The Molten Caldera [Raid] as Perfection.
Blue Insight Runes
-  Shadow Touched Rune: Insight (+48 Fervor) - ?
-  Rune: Ragebourne Insight (+35 Fervor) - Purchased in Fabled Kael Drakkel with "Archivist's Tremissis" currency. Earned from Myrist tradeskill missions, Anchorage tradeskill missions, CD PQs.
-  Celestial Rune: Warlord's Puissance (+25 Fervor) - from the Treasures of Guk Collection . This is the final meta collection reward.
Red Torment Runes
- Tormented Void Rune (+60 fervor, +60 fervor overcap)- Reward from defeating all ROS Heroic Bosses.
Red Paxio Runes
- Ascension of Love, Firmament of Passion, and Foundation of Excitement - Set of 3 red runes that gives +10 fervor and +10 fervor overcap with all 3 equipped.