Cross Patters
These are some of the most essential OLL's in my opinion. Almost all of them are 2-gen.
Sune
R U R' U R U2 R'
Anti-Sune
R U2 R' U' R U' R'
Double-Sune
R U R' U R U' R' U R U2 R'
Triple-Sune
R U2 R D R' U2 R D' R2
Anti-Sune
R2 D R' U2 R D' R' U2 R'
Anti-Sune
Lw' U' L U R U' L' U
Anti-Sune
R U2 R2 U' R2 U' R2 U2 R