Ctrl+Q
I've memorized this shortcut after three uses.
It's beyond my understanding why people keep 10, 20, 30, 40 tabs open. Bookmark if it has useful informatio/content that may merit a revisit or a more in depth reading or viewing. Take notes if there is only a small useful snippet you find useful. And throw the rest away.
Why?! It only equates to lazyness in my mind. Close your browser properly.