If you own these 7 amps, you have > 95% of the world tones:
1. Fender tweed
2. Fender black face
3. Marshall plexi
4. Vox AC30
5. Mesa Boogie
6. Dumble clone
7. High Gain amp like a Bogner Estacy 101B or other
I bet someone will argue that you need fewer and maybe you can make all these sounds happen on fewer, but really these 7 will do just fine.
1. Fender tweed
2. Fender black face
3. Marshall plexi
4. Vox AC30
5. Mesa Boogie
6. Dumble clone
7. High Gain amp like a Bogner Estacy 101B or other
I bet someone will argue that you need fewer and maybe you can make all these sounds happen on fewer, but really these 7 will do just fine.