Outwit is a collection of several command line utilities including winclip.exe, which I use to sort the contents of my clipboard. Copy the items you want, then "winclip -p | sort | winclip -c" to pull the contents, sort it, and push it back on the clipboard. There are far more utilities that put things onto the clipboard than pull them off.
I've also used
Dolphin Text Editor Menu to do this. It adds a number of features whenever you're editing text, even in Notepad. Select the text and hit the hotkey and you get a pop up menu of options from sorting to changing case to removing leading or trailing blanks, etc.