Star Flare:
“A common spell, one every Guardian is urged to take in case of emergency. All it does is send a flare of light into the sky, moving through even solid surfaces unhindered. It’s normally used by Guardians to signal an emergency, that they need backup. It can also be used as a signal for other things.” Selene ch.23
Of note:
This spell was used by 1075 MG in Arcadia as a tribute after learning of Mai’s death wish.
The color of the spell is based on Origin types. Darks send up a purple flare, other color MGs send up their color. (I guess a black flare wouldn't work very well. :) )
Dimensional storage Magic:
Something most MG purchase access to due its to extremely high utility value. Used either with enchanted items, or by purchasing grimoires and using the magic directly.