Keyboard shortcut to switch between Application tabs
That might sound a bit funny now: you spelled  out you answer all the time.

Use Tab to switch between all those controls and "Tabs".

In System Preferences > Keyboard > Shortcuts you might want to enable Full Keyboard Access: All Controls.

Some applications might be too 'dumb' to respect that. For Safari or iTerm: they are not.

Note that while cycling through the Tabs with:


Tab = forward
Shift + Tab = backward


the highlighting halo that indicates your position might be a bit smallish or dim, depending on your settings


Space = select/toggle what is highlighted


Also note the varying options if you talk about browser-like tabs.
The first 10 can be usually switched to directly by using Command+1 etc.

If cycling through browser-like tabs is your goal, the Tab key  also works, but really cycles through all elements. 

To only rotate through the tabs as such use Ctrl+Tab