Hover Peek av Medus24

To turn the extension off, click it in the toolbar.

Hover any link to see a live preview window of the page.
Move these windows around and pin them for reference.
Middle-click a link to open it in a split view next to the current page.
Of course, you can open a window inside another window.

The window opening speed depends on how long it takes the page to load, so the time may vary.

I use it for DnD, where I go through many links in lists, but it's useful all around.
This extension also has a few useful options you can view through your extension settings. (Default is my favourite, so probably no need to change it)