Cartouches enchant creatures, giving them a boost that represents some kind of success or accomplishment. They give the creature they are enchanted to a boost of +1/+1 and a keyword, which is primary in that color. They also carry a secondary enter the battlefield effect, which also directly reflects the flavor of it's color.
Amonkhet cartouches are linked to the Trials of the Five Gods and each Cartouche shares a part of it's name with the trial corresponding to it's color.
) — Create a 1/1 White Warrior with vigilance and give enchanted creature +1/+1 and first strike.
) — Draw a card and give enchanted creature +1/+1 and flying.
) — Put a -1/-1 counter on target creature and give enchanted creature +1/+1 and lifelink.
) — Prevent target creature from blocking this turn and give enchanted creature +1/+1 and haste.
) — Enchanted creature fights target creature and give enchanted creature +1/+1 and trample.
