Home – usually takes the cursor to the start of the current block of text, whether that is a line, a sentence or a paragraph, and is very software-dependent. Different programs handle this different ways.
Ctrl-Home – nearly always takes me to the top of the current document or worksheet. This could have very different responses in other programs, such as databases, for example.
PgUp or Up Arrow – when all else fails.
Those are my general standbys. It’s always possible to write scripts that trap particular keystrokes and do, well, whatever those keys have been programmed to do. For example, on my computer I have set the Alt-< combination to turn down the sound volume 5% at a time, and Alt-> to turn it up 2% at a time.
You can program keys to do nearly anything you want them to OR whatever the software package OR the macro or key interceptor for the file has programmed them to do.
My recommendation if you want to try something like that is AutoHotKey, available for free at https://autohotkey.com.