https://www.amazon.com/Xtreme-Outdoor-Power-Equipment-MA-GT-TROC/dp/B01GU8MGAM
or Stens 255-210x just to name a couple. Do your due diligence.
Toro Master PartsViewer
The Amazon one appears to be the same extreme one as the EBay. Look at the number. Says Fatboy too. Same clutch PSEP.
Here is an Ogura from Rotary OGURA ELECTRIC PTO CLUTCH FOR FERRIS
Then I'd say your choices are to do something to improve clearance so that you can install the other clutch or buy the same OEM clutch.
the square key on the engine shaft can be removed..I tried the Fatboy Extreme and the pulley was to thick or wide so I could not get it behind the frame of the 120 to get it on the shaft. I haven't tried the
Stens. One clutch a company sent me had the square key in the center instead of having the notch which I need. Had to send it back.
I need one with the notch so it can slide over the square key already on the shaft like the one in my picture with the shaft.
I will have to look up the Stens 255-210 and see what it looks like if I can find it on the net.