Defender of the Faith is a secondary quest in the Witcher 3 that is available as you explore Velen.
Guide contains image walkthrough and starting NPC location.

Face Me if You Dare! is a secondary quest that is available in Velen. You will find yourself the unwilling recipient of a challenge from a delusional man. Guide contains image walkthrough and starting NPC location.

Nilfgaardian Lessons – Witcher 3 quest.

Missing in action is a Secondary Quest that is available in White Orchard via a Notice Board. You can help a soldier find the corpse of his brother who was killed in a recent battle. Guide contains image walkthrough and starting NPC location.

Twisted Firestarter is one of the first Side Quests in the game. Blacksmith Willis’ forge has been burned down and you have to find the culprit. Guide contains image walkthrough and starting NPC location.

Imperial Edict Number 18/45 – Witcher 3 quest.

Looking to Borrow a Plough – Witcher 3 quest.

Death to the Invaders! – Witcher 3 quest.

Contract: Devil by the Well is the first Witcher Contract quest you’ll come across in the game. You will have to dispose of a Noonwraith and a nearby Abandoned village. Quest requires some investigation and you have several choice to make. Guide contains image walkthrough and starting NPC location.

Brother Missing is a White Orchard Notice board "side quest" that actually starts the quest Missing in Action (click on this link to see the full screenshot walkthrough)

Gwent: Velen Players – Witcher 3 quest.

Races: Crow’s Perch – Witcher 3 quest.

Fists of Fury: Velen – Witcher 3 quest.

Funeral Pyres is a secondary quest that involves burning the corpses of fallen soldiers. It starts in Velen a bit west of the village of Mulbrydale. Guide contains image walkthrough and starting NPC location.

Ciri’s Room – Witcher 3 quest.

In Ciri’s Footsteps – Witcher 3 quest.

Family Matters is a main quest in The Witcher 3. This quest comes as you complete another main mission called “Bloody Baron”, followed by “Ciri’s Story: The King of the Wolves”. At the end of this quest you can accept to help the Baron once more, or not. If you decide to help him you are given the quest “Return to Crookback Bog”. Guide contains image walkthrough and starting NPC location.

Hunting a Witch is a main quest in the Witcher 3. It is given automatically to you once you’ve completed “The Nilfgaardian Connection” and “Bloody Baron” main quests. Guide contains image walkthrough and starting NPC location.

Pyres of Novigrad – Witcher 3 quest.

Destination: Skellige – Witcher 3 quest.