This app was mentioned in 3 comments, with an average of 6.67 upvotes
So yeah, backstory time. I downloaded this app in hopes of finding out what specific shade of pink Kirby is for drawing reference. (Yes, that's literally the only reason I download it XD) It just said he's "Light Pink" (And also light grey, for some reason? XD) Then I tried on King Dedede, and my gosh I couldn't not share it. X3
I recommend Color Picker over Grab because it not only identifies colors using your camera, but can also do the same with any saved photo in your gallery.
Edit: https://play.google.com/store/apps/details?id=com.nauj27.android.colorpicker
Not the one below.
Some random app
It's pretty shit you'll probably find better if you search
https://play.google.com/store/apps/details?id=com.nauj27.android.colorpicker