Paletton (a.k.a. Color Scheme Designer 4) presents the user with a color wheel and several color scheme styles:

Mono

Complement

Triad

Tetrad

Free style

By moving arrows around the color wheel, users can look at and compare different color palettes suitable for web design, logos, etc. A preview option is available for checking what the color scheme would look like as part of a light or dark website.