A Gift of Silence (or Justice Must be Served)
Type: Crafting
Start: Mages' Collective at Denerim Market District
Destination: Knight-Commander Harrith in Redcliffe Village or Knight-Commander Tavish in Denerim Market District
Task: Bring 10 lyrium potions to either of the Knight-Commanders
Quest Tips: Note that this quest is only active after the attack on Redcliffe by the undead. First, create or buy 10 lyrium potions. You then have a choice to bring the 10 lyrium potions to the knight-commander in Redcliffe Village (Harrith up by the windmill) or in Denerim Market District (Tavish by the estate gate). This sets up whose side you'll be on in the "Defending the Collective" final Mages' Collective quest.
Blood of Warning
Type: Exploration
Start: Mages' Collective at Denerim Market District
Destination: Four doors around Denerim
Task: Mark four blood mage relatives' doors
Quest Tips: As you leave the Mages' Collective in Denerim, open up your map and note the two nearby doors you have to mark. Click on those, then head to the Dirty Back Alley and mark the single door there. The last door is in the Dark Alley, and there may be a large group of thugs waiting to ambush you if you haven't cleared them out already. Dispatch the enemy group and mark the final door for your reward.
Careless Accusations
Type: Exploration
Start: Mages' Collective at Lake Calenhad Docks
Destination: Random encounter in Wooded Glen
Task: Prevent an adventuring group from delivering false testimony
Quest Tips: Shortly after you pick up this side quest, while traveling across the world map, you will trigger a "random" encounter in the Wooded Glen. You can either persuade or intimidate the adventuring party there into not giving false testimony in Denerim, or you can just battle it out for extra experience and loot. It's a relatively simple quest once you find them.
Defending the Collective
Type: Messenger
Start: Mages' Collective at Redcliffe Village
Destination: Knight-Commander Harrith at Redcliffe Village
Task: Deliver the bundled testimony to Knight-Commander Harrith
Quest Tips: If you choose Harrith in the "A Gift of Silence" quest, you will deliver your bundled testimony to him in Redcliffe Village. Otherwise, seek out Knight-Commander Tavish in the Denerim Market District. Pick up your big reward for completing all the Mages' Collective quests.
Have You Seen Me?
Type: Combat
Start: Mages' Collective at Denerim Market District
Destination: Random encounter
Task: Defeat the abomination in the random encounter
Quest Tips: Shortly after you pick up this side quest, while traveling across the world map, you will trigger a "random" encounter in the Out of the Way map. Stun the abomination often and don't give it much chance to counterattack. After it dies, return to Mages' Collective operative for your reward.
Herbal Magic
Type: Exploration
Start: Mages' Collective at Lake Calenhad Docks
Destination: Various places
Task: Present 10 deep mushrooms to the Mages' Collective
Quest Tips: As you adventure, save the deep mushrooms you find until you have 10 and hand them in. If you don't feel like waiting, you can visit the following shops to pick up the deep mushrooms immediately: Lloyd's Tavern in Redcliffe, Olinda's in the Orzammar Commons, Gnawed Noble Tavern in Denerim, and the biggest mushroom stockpile in Alimar's in Orzammar's Dust Town (or Figor's in Orzammar if you've unlocked the door).
Notice of Termination
Type: Messenger
Start: Mages' Collective at Lake Calenhad Docks
Destination: Three separate locations across Ferelden: two in the Denerim Market District and one in the Frostback Mountains
Task: Deliver three termination notes to apprentices across Ferelden
Quest Tips: The toughest part about this quest is traveling to find all three apprentices. Once you find each one, hand him the note and that part of the quest is complete; there is no fighting involved. You can find Sheth in the Wonder of Thedas in the Denerim Market District, Fayd in the center of the Denerim Market District, and Starrick standing out in front of the main doors to Orzammar, by the row of market goods in the Frostback Mountains.
Places of Power
Type: Exploration
Start: Mages' Collective at Denerim Market District
Destination: Four separate locations across Ferelden
Task: Unlock four hidden locations
Quest Tips: The four hidden places of power are: East Brecilian Forest (gravestone in the northern ogre grove), Ortan Thaig (Altar of Sundering), The Alienage (Alienage Tree), and Apprentice Quarters in the Circle Tower (activate the middle of the floor). Because these are in difficult-to-reach places, this will likely be the last Mages' Collective quest you complete before the final "Defending the Collective" quest.
The Scrolls of Banastor
Type: Collection
Start: Mages' Collective at Denerim Market District
Destination: Various places
Task: Collect five scrolls hidden around the world.
Quest Tips: The scrolls are in ancient texts treasure piles in the following locations: Circle Tower (Senior Mage Quarters level, southeast ruined room), Circle Tower (Great Hall level, northwest large room), Wyrmling Lair on the "Urn of Sacred Ashes" quest (southeast library), Wyrmling Lair on the "Urn of Sacred Ashes" quest (middle west barracks), and Werewolf Lair in the Brecilian Ruins (southeast werewolf bedroom). Once you have them all, return for your reward.
See the Circle Tower maps in the "Broken Circle" walkthrough, Ruined Temple map in the "Urn of Sacred Ashes" walkthrough, and Lair of the Werewolf map in the "Nature of the Beast" walkthrough for the Scrolls of Banastor ancient texts locations.
Thy Brother's Killer
Type: Combat
Start: Mages' Collective at Lake Calenhad Docks
Destination: Northern grove in the East Brecilian Forest
Task: Slay the dark Maleficarum Cabal
Quest Tips: To discover the Maleficarum Cabal's hidden ritual, you must first clear the northern grove in the East Brecilian Forest of the ogres that normally inhabit the area. Leave the East Brecilian Forest, then reenter and return to the northern grove. Four dark mages will be chanting in a circle. Speak with them and then the fight is on. If you have Alistair, use his templar abilities to great effect against the mages, especially if you have Holy Smite to drain the mages of mana and deal Spirit damage. A rogue's Dirty Fighting or mage's Crushing Prison can nullify a single target, or Earthquake can knock most or all of them off their feet. If you have distance, and the mages do like to keep their range, return deadly AoE of your own with spells such as Fireball or Inferno. Anti-Magic Ward on your tank will usually mean lights out for at least one of the mages.