cmd + 9 to select last tab
I keep Gmail and my calendar in the first two tabs of my browser and often use cmd + 1 or cmd + 2 to jump to them. The shortcuts continue, with cmd + 3 selecting the third tab, cmd + 4 selecting the fourth, and so on. I rarely jump to the fourth or seventh tab and never the ninth. But cmd + 9 doesn’t jump to the ninth tab, it goes to the last, which I actually want quite often. That’s the stuff I opened most recently!
cmd + option + left and cmd + option + right navigate between tabs if you’re close to the one you want.