I use two palettes for the majority of my work: a Winsor & Newton Cotman Field Sketch Box for my sketchbook work; and a John Pike palette for my studio work. I use Holbein transparent watercolor for both palettes.
The field sketch box comes with student grade half pans which I remove and replace with a squirt from the tube. I do not fill the Pike palette with the entire contents but rather refresh the palette before each painting session with a small amount of paint. I spray both palettes with water a few minutes before painting to make sure the paint is nice and juicy.
Here are my colors:
Permanent Alizarin Crimson
Cadmium Red Light
Permanent Yellow Orange
Gamboge Nova
Greenish Yellow
OLive Green
Cobalt turquoise Light
Cerulean Blue
Cobalt Blue
Marine Blue
Ultramarine Blue
Mineral Violet
Raw Sienna
Burnt Sienna
Burnt Umber
For the present time I no longer use Opera, or Titanium White, if I can help it, although it is shown in the above photo.
I leave out Greenish Yellow, Cobalt Turquoise Light and Mineral Violet when using the field box as it only has twelve slots.