Scrolling to the bottom of 500 emails
Solution 1:
A fast way to get back to the top from anywhere in the list is to tap the status bar above the list. This works in many places throughout iOS, like Safari, Notes, etc.
The only fast way to the bottom, though, is to swipe as fast as you can!
Solution 2:
To get back to the top quickly, you can filter your email by unread. This takes you to the top of your unread emails. Tap/open on your first email then go back tap again to unfilter.