The first three are the Seiler workout durations that he studied, of which he found that 8 mins with 2 minutes rest to be most effective. I don’t believe that 108% of FTP was actually specified or even remotely achievable for most people with that little rest.
40/20s are pretty standard and you can do them at a variety of different intensities depending on what you are after.
Depends on what you are after in terms of adaptation. Here are a few names to get you started, and make sure to check out the +1 through +6 variants.
- Mount Deborah
You can use the workout filters to get pretty much anything that suits your needs.