I had a load of plasmoids, beginning with plasma-widget- and kde-applet and kde-plasmoid-, which I think I had added from a PPA, but I can't for the life of me find which one it is (I did a fresh install). I have already tried the backports (first PPA I added anyway), but it isn't the one.
Plasmoids / Plasma-widgets
The Ubuntu is using the plasma-widget-* as the package name: http://www.kubuntuforums.net/showthread.php?38465-Plasmoids-are-now
KDE plasmoids - from the Ubuntu repositories and from the Kubuntu developers PPA
Plasmoids (binaries) source is from the KDE-apps or somewhere - The Ubuntu repositories and the Kubuntu developers PPA have the package
Third party ppa
Example: plasma-widget-daisy -> PPA search: https://launchpad.net/ubuntu/+ppas?name_filter=plasma-widget-daisy
The plasma scripts can be downloaded/installed from the add-widgets action: