Webflow only accepts HTML Hex RGB.
That would be great to be able to paste colors in many formats. Even if they're just converted into Webflow's color right away.
Here are the formats I often come across followed by a value example for the color #C1D321
Hex RGB 0xC1D321
Hex RGBA 0xC1D321FF
CSS RGB rgb(193, 211, 33)
CSS RGBA rgba(193, 211, 33, 1)
There are others but they're not very relevant for Webflow designers:
Float RGBA 0.756 0.827 0.129 1
Float HSVA 0.183 0.843 0.827 1
CSS HSL hsl(66, 73%, 48%)
CSS HSLA hsla(66, 73%, 48%, 1)
Although, if you have a designer working with Webflow on a HTML5 portion of a mobile app, the suppot of the 4 formats above could be a blessing.
Also, as there is little color palettes management on Webflow at the moment, that would be cool to be able to copy/paste color values with their opacity... so CSS RGBA or Hex RGBA.