This is a rundown of the most-encountered player actions that I would
consider easy or hard, starting with 1 as the easiest to rebuild and
going up from there to the hardest.

 1. Cable Euphona Inner-Player
 2. Aeolian, non-reproducing
 3. Standard action
 4. Gulbransen screwed stack
 5. Steger
 6. Wurlitzer
 7. Schulz
 8. Gulbransen glued stack
 9. Melville Clark Apollo
10. Farrand Cecilian
11. Duo-Art reproducing action

Feel free to inform me of other actions and the level of skill required
to rebuild them.

Luke Myers
ldmyers95@gmail.com