If you use Burp Suite a lot then you’ll no doubt love the interface – moving between tools is really fast and the interface is just friendly; however I recently heard someone complaining that it’s annoying that it’s mouse-only and you can’t use hotkeys to swap between tabs and move between tools…but you can!
It’s all there by default, it just seems that many people I talk to haven’t seen the right tab, so to save you all digging around here’s a screenshot of the right bit:

So they’re all there and they’re there by default, a quick TL;DR of my favourites:
Sending Send to Repeater Ctrl+R Send to Intruder Ctrl+I Forward intercepted Proxy message Ctrl+F Switching Toggle Proxy interception Ctrl+T Switch to Target Ctrl+Shift+T Switch to Proxy Ctrl+Shift+P Switch to Scanner Ctrl+Shift+S Switch to Intruder Ctrl+Shift+I Switch to Repeater Ctrl+Shift+R Go to previous tab Ctrl+Minus Go to next tab Ctrl+Equals Searching Previous search match Ctrl+Comma Next search match Ctrl+Period Encoding URL-encode key characters Ctrl+U HTML-encode key characters Ctrl+H Base64-encode Ctrl+B
(Add shift to invert, e.g. Ctrl+Shift+U to URL decode)