Where can I get replacement triangle sanding pads that don't suck?

I want replacement Velcro back triangle sanding pads. I want 100, 120, 150, and 180 grit I found 120 and 180, but I can't find 100 or 150. Also I want pads that fit the 3.75/3.75 backing. Ones In home depot and Lowe's are kind of small, and I just don't trust the garbage on Amazon. Any recommendations?