Here's a full list of cards with changes in rarity included in the first Modern Masters set released in 2013. Some cards do have a new art but some just don't. On my next article, I will include Modern Masters 2015 and when Modern Masters 2017 is completely spoiled, Check out all the cards that shifted rarity:
Terashi's Grasp
From Common to Uncommon
Mulldrifter
From Common to Uncommon
Death Rattle
From Common to Uncommon
Executioner's Capsule
From Common to Uncommon
Horobi's Whisper
From Common to Uncommon
Desperate Ritual
From Common to Uncommon
Grinning Ignus
From Common to Uncommon
Tribal Flames
From Common to Uncommon
Manamorphose
From Common to Uncommon
Bound in Silence
From Uncommon to Common
Otherworldly Journey
From Uncommon to Common
Test of Faith
From Uncommon to Common
Dampen Thought
From Uncommon to Common
Perilous Research
From Uncommon to Common
Petals of Insight
From Uncommon to Common
Street Wraith
From Uncommon to Common
Syphon Life
From Uncommon to Common
Warren Weirding
From Uncommon to Common
Crush Underfoot
From Uncommon to Common
Hammerheim Deadeye
From Uncommon to Common
Thundering Giant
From Uncommon to Common
Hana Kami
From Uncommon to Common
Imperiosaur
From Uncommon to Common
Moldervine Cloak
From Uncommon to Common
Walker of the Grove
From Uncommon to Common
Feudkiller's Verdict
From Rare to Uncommon
Take Possession
From Rare to Uncommon
Auntie's Snitch
From Rare to Uncommon
Mad Auntie
From Rare to Uncommon
Pardic Dragon
From Rare to Uncommon
Masked Admirers
From Rare to Uncommon
Reach of Branches
From Rare to Uncommon
Worm Harvest
From Rare to Uncommon
Epochrasite
From Rare to Uncommon
Auriok Salvagers
From Uncommon to Rare
Aether Vial
From Uncommon to Rare
Yosei, the Morning Star
From Rare to Mythic Rare
Keiga, the Tide Star
From Rare to Mythic Rare
Vendilion Clique
From Rare to Mythic Rare
Dark Confidant
From Rare to Mythic Rare
Kokusho, the Evening Star
From Rare to Mythic Rare
Kiki-Jiki, Mirror Breaker
From Rare to Mythic Rare
Ryusei, the Falling Star
From Rare to Mythic Rare
Jugan, the Rising Star
From Rare to Mythic Rare
Sword of Fire and Ice
From Rare to Mythic Rare
Sword of Light and Shadow
From Rare to Mythic Rare
Vedalken Shackles
From Rare to Mythic Rare
Tarmogoyf
From Rare to Mythic Rare