How to unhide an extension in Chrome?

I installed a Chrome extension, it had a small icon in the top bar between the URL and the three-dots menu.

Then, I hide the extension, thinking I would not need it anymore.
But now, I realize I want to always see this extension's icon, so I want to unhide it.

Most online solutions talk about small icons above "New tab", but I have no such icons, despite having dozens of installed extensions, most of them hidden:

Chrome 79.0.3945.130 on Mac 10.15.2

3 Answers

The method of hiding or showing extension icons in chrome has changed. There is now an Extensions icon that looks like a puzzle piece to the left of the round User icon, and if you left-click on that it allows you to pin or unpin the extension icons from the toolbar.

Icon:

After right-click, you can pin/unpin extensions:

(screenshots taken with Chrome version 84.0.4147.89)

UPDATE: Chrome changed how this work. Please see the fine answer from @JDGillis on how this works now (mid- and late-2020), not my answer below. Of course, it may change again in the future!

According to :

To show extensions you've hidden, click the right side of your address bar and drag it to the left. To bring hidden extensions back to your toolbar, click More More. Right-click the extension's icons, and select Show in toolbar. Some extensions don't have this option.

This is how it looks like when the cursor symbol changes.

This is NOT obvious but it works if you do it exactly: grab the right "edge" of the address bar (just to the right of the Add-Favorite star), and drag the edge to the left. Any hidden extensions show back up!

I'm not sure what the other suggestion from Google is for (right-click on the icon), as I didn't need to do that to keep the icon back visible again after dragging the address bar to the left.

Restarting Chrome solved the problem.

It must have been in some weird ready-to-update state.