Gloobus Preview is described as 'Gloobus-preview is an extension of GNOME designed to enable a full screen preview of any kind of file. It lets you view files so quickly without having to open them in their normal software'. There are six alternatives to Gloobus Preview for Linux, Windows, Mac and Linux Mint. The best alternative is QuickLook, which is both free and Open Source. Other great apps like Gloobus Preview are Eye of GNOME (Free, Open Source), Seer (Freemium), WebPQuickLook (Free, Open Source) and xviewer (Free, Open Source).
Background : One of the few features I missed from Mac OS X is Quick Look. It allows user peek into a file content in a lightening speed by just pressing the Space key. Windows, on the other hand, does not has this handy feature ... until now.
Eye of GNOME is the official image viewer for the GNOME Desktop environment. With it, you can view single image files, as well as large image collections. The Eye of GNOME supports a variety of image file formats.
By default, macOS doesn't provide previews and thumbnails for WebP, a modern image format providing superior, lossless and lossy compression for images on the web. WebPQuickLook fills this gap by allowing you to see previews and thumbnails of .webp images on your Mac.