Utility to discover PowerPC apps and widgets?

The closest thing I can think of is go Apple Menu > About this Mac > More Info

Then click Applications and then sort via kind (you might have to scroll over, then just click the header). I don't think there is a such thing as a non universal widget since they are just HTML / CSS.

 

If you're only wondering about running apps, open up Activity Monitor. One of the columns lists whether the given process is running as an Intel or PowerPC binary.

Widgets can (and some do) include compiled binaries. PearLyrics in particular is definitely a PowerPC widget and while it works fine on an Intel Mac, it does run in Rosetta.

 

Well, if you don't care about searching through every app or only want to check certain apps, you can Right-click or Ctrl-click and select "Get Info". Under "General", there is a "Kind" label that will tell you whether the app is Universal, Intel, or PowerPC. If you want to find them all at once, Benjamindaines's suggestion appears to be the best one.

 

The fastest way for you to find out which apps you have are PPC or UB is by going to the System Profiler. Once there go to the Software heading, and there select Applications. In the Kind section you can see if the app is PPC, UB, or Intel.