Default Mystic Code. This is the only MC that you will have access until you get to London, assuming you did not have a chance to get a time-limited Mystic Code. More on that later.

Chaldea
Skills:
>First Aid - Heal one servant up to 3000 hp.
>Momentary Reinforcement - Increase on servant's attack by up to 50% for one turn.
>Emergency Evasion - One servant evades incoming attacks for one turn.*
*This status effect will not allow you to dodge Sure-Hit status effects your opponent may be using, such as Sasaki Kojiro's 'Sense of Subtle Elegance.'


Unlockable Mystic Codes. These are unlockable after London has been accessed. They are gained through quests in the Chaldea Gate above the daily quests. The quests do not expire.

Combat Uniform
Skills:
>Reinforce All - Increase all servant's attack by up to 30% for one turn.
>Gandr - High chance to stun one enemy for one turn. Enemy servants may have slight chance to evade.
>Order Change - Exchange one servant on the field for another servant in the back. The number of command cards for that servant will be the same, but the cards will change correctly to that particular servant.

Mage's Association Uniform
Skills:
>Heal All - Heal all servants up to 2800 hp.
>Spiritron Transfer - Increase one servant's NP chance by 20%.
>Command Shuffle - Dispose of the 5 commands cards you have now and exchange them for 5 new command cards.*
*One anon has specifically mentioned that it is not exactly randomized as the skill states. If you are on turn 1/4/7/a turn the deck has reset completely, the cards will be 5 of the 10 cards that have not been shown yet. If you are on turn 2/5/8/a turn after the deck has reset, it will be the last 5 cards that have not been shown. If you are on turn 3/6/9/a turn the deck is on its last 5 command cards, it will be a 100% randomized shuffle of the deck and it will act as if the deck was reset to turn 1.

Atlas Academy Uniform
Skills:
>Dust of Osiris - One servant has invulnerability to all damage for one turn.*
>Rain of Isis - Cure one servant's debuffs.
>Eye of Medjed - Reduce the cooldown of one servant's skills by two.
*This status effect will not allow you to dodge Pierce-Invulnerability status effects your opponent may be using, such as Li Shuwen's 'Juezhao.'

Time-Limited Mystic Codes. These were only available for a limited time frame and as such, if you do not have them, you cannot receive them normally. The only exception may be Da Vinci's Rare Prism shop, where she currently is selling one of the MCs for 5 Rare Prisms.

Anniversary Blonde (Time frame: February 3, 2016 to February 10, 2016)
Skills:
>Mana Burst - Increase one servant's Buster card damage up to 60% for one turn.
>Conviction of Victory - Increase your critical star amount up to 20 stars for one turn.
>Knight's Oath - Grant one servant a Guts status for one turn. If Guts is activated, the servant will revive with a maximum hp of 4000.

Royal Brand (Time frame: April 21, 2016 to April 27, 2016)
Skills:
>Reaction Enhancement - Increase one servant's Quick card damage up to 50% for one turn.
>Iron Will - Increase one servant's critical star absorption up to 1000%.
>Unavoidable Strike - Grant one servant a Sure-Hit status for one turn.

Brilliant Summer (Time frame: August 11, 2016 to August 31, 2016)
>Rumble Party - Increase all servant's Quick card damage up to 30% for one turn.
>Sure-Kill Trident - Grant one servant a Pierce-Invulnerability status.
>Sea House Shower - Increase one servant's hp by up to 3000 hp and increase their NP charge by 10%.

Memories of the Lunar Sea (Time frame: November 3, 2016 to November 9, 2016)
>Spiritron Elevation - Increase one servant's Arts card damage up to 50% for one turn.
>Groundwork For Complete Victory - Increase one servant's critical star generation for one turn.
>Punishment - Prevent one enemy from applying buffs to themselves for a one time effect.