Tip: On Cinnamon (and probably other Window managers and OSes), Alt + ~ is the same as Alt + Tab, but restricted to the currently active application (e.g. tab between Firefox windows).
Learned this from last year and I've probably used it every day.
@pganssle cool to see they adopted this, I believe it was a feature first on Unity as we adopted per-application switcher grouping.
Not sure about others, but on Unity we looked at the keyboard map and it is actually "the key above tab" which may not be ` for some folks.