Apps with 'Image stacking' feature

digiKam is an advanced digital photo management application which makes importing and organizing digital photos a "snap". The photos are organized in albums which can be sorted chronologically, by folder layout or by custom collections.

DeepSkyStacker is a freeware for astrophotographers that simplifies all the pre-processing steps of deep sky pictures.

Siril is an astronomical image processing tool, able to convert, pre-process images, help aligning them automatically or manually, stack them and enhance final images.

Starry Landscape Stacker makes it possible to produce landscape photographs taken at night that have both low noise and stars rendered as points.

Zerene Stacker is “focus stacking” software designed specifically for challenging macro subjects and discerning photographers. Of course it works great with simpler subjects, close-ups, and landscapes also!.

PixInsight - Advanced Image Processing. PixInsight is a modular, open-architecture, portable image processing platform available for FreeBSD, Linux, Mac OS X and Windows.

Sequator is a free software which can track stars on multiple images, align stars and stack them.