The title says it all. Fresco's eye dropper tool can optionally pick up multiple colors simultaneously (not unlike a certain Mixer Brush setting in Photoshop), allowing you to draw with multiple colors at once. This is awesome because it lets you use multiple colors in a single stroke for other tools, like Brushes. You should also be able to change the hue, saturation, and value of the stamped colors (Like in Adobe Fresco, as seen in the video below). There's no reason that Photoshop shouldn't have this feature too.
The following Adobe youtube video starts with the line "Multicolor selection is a powerful new feature in Adobe Fresco that will open up a world of possibilities for artists..." I can't help but wonder why those possibilities haven't yet made it to Photoshop artists-- especially considering this video came out in May of 2020 and it's nearly 2022 now. Check out the video to see how the mechanic works: