Waybackpack - Download the entire Wayback Machine archive for a given URL
Hover Zoom - Enlarge thumbnails on mouse over.
YouTube Decade - Watch the most viewed videos posted exactly 10 years ago
Imagus - The extension is intended to complement image features that (I think) is missing from Opera by...
Buffer - Buffer makes it super easy to share any page you're reading. Keep your Buffer topped up and we automagically share them for you through the day.
Image Max URL - Help find larger or original versions of images, including a customizable image popup feature