Here's a diligence tracker (and request list) that I built and have used on several deals. I find it helpful because:

1) You can keep track of everything (including notes) in one place.
2) You can easily coordinate all buyer and seller stakeholders.
3) You can empower the seller to organize materials in the correct folders (I set up Google folders).
4) You have a template you can iterate on for future deals.

https://docs.google.com/spreadsheets/d/1xWtV_JlGpAz3G0gGaKly3p-Qg55kmCAh/edit#gid=###-###-####