Andrew Swarbrick Set
Flat magnums. They are so versatile for "cutting in" near the edges and being able to form hard edges to shading or colouring without needing to switch groupings to rounds or liners.
Curved magnums for large areas of shading or smooth colour blends.
Round shaders. The most recent addition to my toolbox, great for small areas of colour or non tight lines within designs.
Round liners, namely the 7 round liner, I find anything smaller to be too small to have any lasting impact on my large scale tattoos in terms of longevity. The 7's are great for tidying up edges and specular lighting on textures, skin, and eyeballs. I use larger liner groupings for powerlining or to have linework as part of the actual design.