The first notable coincidence in the series is with Paper Mario and Super Mario Galaxy 1.
The coincident part is when Peach's castle gets lifted into the air.
The second coincidence is is with Super Mario 64 (64DS) and Super Mario Galaxy 2.
The coincident is in Peach's letter where she invites Mario to her castle for cake.
The third coincidence is also with Paper Mario: The Thousand Year Door and Super Mario Galaxy 2 in the end where Peach is held in a bubble before the main villain in the game.
Feel free to expand on the coincidences mentioned or add more coincidences that are seen throughout the series.
The coincident part is when Peach's castle gets lifted into the air.
The second coincidence is is with Super Mario 64 (64DS) and Super Mario Galaxy 2.
The coincident is in Peach's letter where she invites Mario to her castle for cake.
The third coincidence is also with Paper Mario: The Thousand Year Door and Super Mario Galaxy 2 in the end where Peach is held in a bubble before the main villain in the game.
Feel free to expand on the coincidences mentioned or add more coincidences that are seen throughout the series.