Here is the full list of all 19 Rainbow Mix trophies - there are 3 bronze, 6 silver, 9 gold and 1 platinum.
Complete all challenges
Guess 25 colors incorrectly
Guess 10 colors incorrectly
Guess 5 colors incorrectly
Guess 75 colors in normal mode correctly
Guess 75 colors in kids mode correctly
Guess 50 colors in normal mode correctly
Guess 50 colors in kids mode correctly
Guess 40 colors in normal mode correctly
Guess 40 colors in kids mode correctly
Guess 30 colors in normal mode correctly
Guess 30 colors in kids mode correctly
Guess 20 colors in normal mode correctly
Guess 20 colors in kids mode correctly
Guess 10 colors in normal mode correctly
Guess 10 colors in kids mode correctly
Guess one color incorrectly
Guess one color in normal mode correctly
Guess one color in kids mode correctly