On Chrome, you can join tabs into a colored group with a name and then collapse that group so that it occupies considerably less space in the bar. Useful to organize your browsing into tidy buckets.

On Firefox, there's no adequate innate manner of doing that. But the browser has an add-on called simple tab groups that uses a native "hidden tabs" feature to make a similar approach. The difference is it adds a button to the left that becomes a drop-down menu, and each of the entries is a colored and named group, and pressing one, hides the rest and bring up the tabs you previously in the one selected.

I find either just as good, and instrumental to browsing. For example, I have a red group just for YouTube, where like 20 tabs are open and to or from which I occasionally drag a tab.