I hope this list of accesskeys to be somewhat helpful.
Some of these accesskeys may not work while using a particular screen reader, or even not work at all.
Some accesskeys need Enter to be pressed even in Firefox e.g. “h". (The reason is duplicate definition of these accesskeys on the page. Would be nice if Twitter corrected this.)

• 0 Skip past navigation
• 1 Home
• 2 Skip to footer
• 3 Jump to the sidebar
• d Direct messages sent only to you
• f Favorites
• h Home
• i Send a direct message
• l Sign out
• m Tweets mentioning you
• n Results update
• o Direct messages you’ve sent
• p Profile
• r Retweets by others
• s Settings

The following group will not work on Firefox, since Firefox requires Alt+Shift to activate accesskeys.

• > Send a direct message
• = (equal sign) Find People
• ? (question mark) Help
• / (forward slash) Search