This list took some time to make so I hope you appreciate it

Dawn (10G)
Completed mission 1 on any difficulty.

Requiem (10G)
Completed mission 2 on any difficulty.

Forerunner (10G)
Completed mission 3 on any difficulty.

Infinity (10G)
Completed mission 4 on any difficulty.

Reclaimer (10G)
Completed mission 5 on any difficulty.

Shutdown (10G)
Completed mission 6 on any difficulty.

Composer (10G)
Completed mission 7 on any difficulty.

Midnight (10G)
Completed mission 8 on any difficulty.

Wake Up, John (20G)
Completed the Campaign on Normal or harder.

I Need a Hero (40G)
Completed the Campaign on Heroic or harder.

The Legend of 117 (70G)
Completed the Campaign on Legendary difficulty.

Lone Wolf Legend (90G)
Completed the Campaign solo on Legendary difficulty.

Skullduggery (15G)
Completed any Campaign mission with 3 or more Skulls on Heroic or harder.

Bropocalypse (10G)
Completed any Campaign mission cooperatively on Heroic or harder.

Contact the Domain (10G)
Found a Terminal in the Campaign.

Terminus (50G)
Found all of the Terminals in the Campaign.

Digging up the Past (20G)
Found and accessed Chief's record in mission 1.

Midnight Launch (20G)
Got significant air in the Warthog at midnight in mission 2.

This is my Rifle, This is my Gun (20G)
Carried a UNSC weapon all the way through mission 3 on Heroic or harder.

Bros to the Close (20G)
Completed mission 4 without one preventable Marine death on Heroic or harder.

Mortardom (20G)
Hijacked a Wraith and used it to kill at least four enemy Wraiths in mission 5 on Heroic or harder.

Explore the Floor (20G)
Tricked or forced a Hunter to fall to his demise in mission 6.

Give Him the Stick (20G)
Took out both Hunters using only the Sticky Detonator in mission 7.

Chief, Smash! (20G)
Killed 3 Crawlers in one hit with the Gravity Hammer in mission 8.

Not Some Recruit Anymore (15G)
Ranked up your Spartan-IV to SR-5.

Movin' On Up (25G)
Ranked up your Spartan-IV to SR-20.

I <3 Red vs Blue (15G)
Won 5 War Games matchmaking matches.

Hanging on the Combat Deck (30G)
Won 20 War Games matchmaking matches.

Operation Completion (15G)
Completed a Spartan Ops Mission on any difficulty.

A Legendary Episode (40G)
Completed all chapters in Spartan Ops Episode 1 on Legendary difficulty.

Dedicated to Crimson (80G)
Completed all chapters in the first 5 episodes of Spartan Ops on any difficulty.

Crimson Alone (20G)
Completed a Spartan Ops chapter solo on Legendary.

Roses vs Violets (20G)
Found one of the RvB Easter Eggs in Spartan Ops.

No One Left Behind (20G)
Saved at least one Marine in Chapter 3 of Episode 2 of Spartan Ops on Heroic or harder.

Knight in White Assassination (20G)
Assassinated a Knight in any Spartan Ops mission.

What Power Outage? (20G)
Completed Chapter 4, Episode 5 of Spartan Ops without losing a generator on Heroic or harder.

No Easy Way Out (20G)
In Ch 1, Ep 5 of Spartan Ops survived the enemy assault during the defense on Normal or harder.

The Challenged (10G)
Completed a Challenge.

The Challenger (20G)
Completed 25 Challenges.

Armorer (5G)
Changed your Spartan's armor in the Spartan Armor card.

Badge (5G)
Changed your Emblem in the Spartan ID card.

PWND (5G)
Changed your Service Tag in the Spartan ID card.

What a Poser! (5G)
Changed your Spartan's pose in the Spartan ID card.

The Cartographer (5G)
Created and saved a Custom Map in Forge.

Game Changer (5G)
Created and saved a Custom Game type in War Games.

Snapshot! (5G)
Saved a Screenshot from the Theater.

The Director (5G)
Saved a Film Clip from the Theater.

Sharing is Caring (5G)
Uploaded a File to your File Share.

Bromageddon (40G)
Completed the Campaign cooperatively on Heroic or harder.