Nice question as far as it goes.

But it would have been nice to go a bit further and have a few more backup types, a list like

Database backup

Differential database backup

Partial backup

Differential partial backup

File backup

Differential file backup

Log backup

(plus of course incremental backup and maybe more spurious ones)

so that it's clear that the Database/Partial/File distinction is orthogonal to the Full/Differential distinction, giving 6 possibilities plus the log backup to make 7.

And then does WITH Copy Only introduce some more types and if so how many - but maybe that could be a separate QotD.