First off, thank you for the great work you do every day.
I am aware that you currently don't have hotkeys/keyboard support.
I wish to suggest you include hotkeys where possible, specially the more intuitive ones that are expected to work.
One example of basic shortcuts that should work is when you check some Tickets to delete them, having the "del"/"supr" key do the job instead of clicking the "delete" button in the UI.
Another basic example is to press "Ctrl+Enter" to submit a comment/email in a thread. This is a standard shortcut to submit in most enterprise softwares.
I realize that adding a customization view allowing to tweak every shortcut is an entirely different thing. That's why my suggestion emphasizes the support of basic and intuitive shortcuts.
HubSpot is all about organization and agility, and shortcuts play a big role is allowing users to customize and navigate their routinely tasks more smoothly.
Hope you can take this into account and thanks again for the great work.