Like mentioned above, there are so many options that it's hard to narrow down 8-12 colors to start with. I'll simplify as much as possible. You need 2 base coat primers. Light and dark. I use auto air autoborne sealer white and black. The overall base color will determine which I will use to prime my bait with. Then you will want transparents, opaques and pearls/flakes. You will need bright fluorescent colors, earth tones and good old white and black (non sealer).
As mentioned above, some of my patterns will have between 10-25 different colors used in a variety of ways. Mixing and layering colors can turn 2 bottles of paint into a dozen different colors. I'll try and make a list of colors I have to have. But this is just my opinion.
Sealer white
Sealer black
Opaque white
Opaque black
Fluorescent yellow
Fluorescent orange
Brown
Green
Blue
Pearl gold
Pearl white
Purple
With those colors, you can get numerous different colors by mixing or layering. For example, mix black with Pearl white to make Pearl silver. Mix blue with Pearl white for Pearl blue and so on. This is really hard lol. I have about every color made in water based and solvents. Plus dry pearls and flakes along with specialty paints like chrome. Hope this helps rather than confuses you. But I've been at this since the late 90's and I'm still adding new brands and colors every week. You will build up a pile of colors over time if you stick with it good luck.