Read the grid from left to right, on the top is 1 to 4 and the letters correspond to the first letter of the color.
R1 = OTA + BTA
R2 = OTA +BTA
R3 = Taken
R4 = Taken
O1 = OTA + DTA
O2 = Taken
O3 = Taken
O4 = Taken
Y1 = Taken
Y2 = OTA + DTA
Y3 = Taken
Y4 = Taken
G1 = Taken
G2 = Taken
G3 = Taken
G4 = Taken
B1 = BTA + DTA
B2 = Taken
B3 = Taken
B4 = Taken
There are a few left, go wild my dudes! Also, just because it isn’t marked as taken, if there are quite a few comments before yours please understand that the one you are asking about may be already taken.