I made my own by tiling,
Generally an icon file will contain 3 sizes at the same time:
When viewed as tiled it's 48 x 48,
When viewed as icons it's 32 x 32,
When viewed as a list it's 16 x 16,
I've tried them separately 128*128 64*64 48*48 32*32 16*16
Obviously the first icon is the clearest (used 48*48)
The second one is 128*128, not the bigger the size the clearer it will be, lots of jaggedness. Depends on the situation.