Yes we need a lot more information on this.
7 colors can either be "multi color LED" with 7 color zones on the keyboard, or can be a RGB LED with basic (beginner level, to be honest) defined steps stemming from pure RGB combinations:
Red, Green, Blue,
Yellow (RG), Cyan (GB), Magneta (RB).
White (RGB), Black (off).
If black isn't considered a color, there you are.
Most "7 color" RGB keyboards won't allow you to mix various channels of RGB brightness levels together.
The Void Ray teamwolf RGB and E-Element RGB keyboards are limited to 7 colors. There's multiple brightness levels (16 on the void ray) BUT you can't mix RGB channels together so you can't mix the brightness levels at all, so you're limited to those 7 presets.
RGB keyboards that allow you to mix brightness levels per different color channels together can vary between 512 colors (8 brightness levels of RGB)->Corsair basic color palette, Ducky Shine 5 RGB key tapping (hardware) 8 brightness levels, Coolermaster Masterkeys key tapping (hardware), etc, or 262,144 to 16.7 million colors (Ducky shine 5 PWM key hold+release hardware cycling (64 levels R, G, B mixing)), Corsair 16.7 million mode (RGB Strafe only, software only), Coolermaster masterkeys Pro L/S (Software only)