Plenty.... You're going back to the basics but with more information and more precision. My own checkride is this Friday. You're also going back to VFR flying. It's a change from the IR to get used to.
- Airplane Flying Handbook (FAA)
- Pilot's Handbook of Aeronautical Knowledge (FAA)
- Commercial Pilot PTS
- Commercial Pilot Oral Exam Guide (ASA)
- FAR/AIM
- AC 61-67
- AC 90-48
- AC 90-66
- AC 120-51
- Chart User's Guide
- POH for your testing airplane
If you can get your hands on a Jeppesen Commercial text to borrow, get it. They have some awesome backup explanations and great depictions on systems you'll want to know. So much more from the FAR/AIM is a must to know just as Chapter 5 was during IR. "Little things" such as 91.519 for passenger briefing, I thought I knew "well enough" can bite ya. I actually created a short list and taped it in my checklist.
There are more but I cannot recall all those I've looked at. I've dug up some info on the web.
Whittsflying.com is a great resource but it's hard to get into. The man is a powerhouse of knowledge but he's not the best at organizing it on-line.
If you don't have a manual for the plane, get one. You're going to want one with you at all times you study, not to mention some serious preflight planning. You'll have dreams on some nights about systems. If it's a hard-to-find manual,
http://www.esscoaircraft.com/ is an awesome source. They are great on Piper's but the older Cessna RG's are more expensive. Direct from Cessna was cheaper for the 182RG for $80 but I found it within a week on eBay for $42 and that included three other older Cessna manuals. Sometimes, you can find it alone for about $20. Just put up search tools for the manual you want. But, you do need to keep one with you.
The Ac's I listed are those most emphasized on me. There are few others. I'll be walking into my oral with a copy of each in a small binder.
Within a short time of taking your Commercial written, take the CFI written. The knowledge will be fresh and it's a good way to refresh on the way to Commercial oral as well as going into CFI training.
I hope I've helped. One thing I'm trying to do is train and prepare for the checkride, not the DPE. I made the mistake of flying too much early on and slower in knowledge just before the written. Then, I had a personal issue get in the way and lost a month. After that, I flew too much and didn't study. While my maneuvers were within PTS, I learned the hard way I had lost a lot of what I had studied. Tapping into others and getting quizzed (without having to pay a ground instructor) would help along the way.
Best of Luck to ya!