Hover Zoom - Enlarge thumbnails on mouse over.
Vimcal - Vimcal is the world’s fastest calendar, beautifully designed for people who work remotely and live in their calendars.
Imagus - The extension is intended to complement image features that (I think) is missing from Opera by...
Clean Google Calendar - Makes Google Calendar look nicer & launches as a desktop app
Image Max URL - Help find larger or original versions of images, including a customizable image popup feature
Plan - Plan is a better way to organize.