For me, it's:

• mod + return for terminal
• mod + e for file manager
• mod + r for dmenu/bemenu
• mod + d to switch to the next empty workspace.

All because I have to work with win10 workstations and using a different, superior shortcut scheme would mess up my muscle memory. Remembering to use shutdown -s -f -t 0 instead of poweroff is difficult enough, and don't even get me started with the audacity to use curl as an alias for Invoke-WebRequest!