Some more holes for OP to consider:
- EH 8. The pin placement makes this hole especially tough. EH 3 is always a tough cookie, for me at least. Your approach have to hit the ridge behind the pin just right for it to roll back for a good birdie look; go past the ridge and say hello to bogey.
- WC doesn't have many tough holes, but 10 and 14 do stand out.
- Pebble Beach's gauntlet of 8,9,10. For extra vindictiveness, add them together.
- Pinehurst 16 is not as hard as its F9 counterpart 4, but it definitely belongs in the "hardest par4" group in WGT.
- RSG 4 is a sleeper hole because of its savage green.
- Olympic 5. This hole causes more headaches that it should because of the right dogleg that forces you to play into the overhanging tree on the right side.
- CCC 4. Immediately off the tee you are forced to carry a huge tree. The approach play severely uphill, and the pin is cut very close to the front to boot. Another tree just off the left side of the green is ready to catch off-line shots. Honorable mention: 14 and 15.
- Bethpage 7 (front right pin), and of course 15.
- St Andrews 2, and 13.
- Kiawah 18.