Shadowlord is a simple color tint and shade generator that allows you to enter any percent from 1 to 100 to control your output.
ColorHub is a color tool that helps web developers find the perfect color palette for their next project. Simply select a palette, edit and preview it on a range of layouts, and export a CSS, SCSS, or Tailwind snippet.
Huemint is a palette color generator that uses machine learning. It lets you instantly visualize your color scheme in a logo mockup, website, or illustration.
Color Leap is a collection of 180 color palettes showcasing colors used throughout 12 historical eras. Each palette was created by sampling pieces of artwork from the time period.
Color Psychology by Nick Kolenda
This great comprehensive article from Nick Kolenda's blog will teach you the color psychology in marketing, what each color means, how colors influence us, and more.
Adobe Color is an online tool that allows you to make, browse, and save color palettes using a color wheel or extraction of colors from an image.
0 to 255 Color Picker
This nice and simple color picker allows you to enter any color and get all its variations/shades.