Free open source alternative app list of Krpano :

Photo Sphere Viewer

A JavaScript library to display Photo Sphere panoramas.

FreeWindowsmacOSLinuxAndroidiOS

Opanorama.js

A 360-degree JS library based on Threejs with both gesture and gyroscope support.

FreeWindowsmacOSLinuxAndroidiOS

Tpanorama

A very easy to use panorama generation, panorama mark editing plug-in!

FreeWindowsmacOSLinuxAndroidiOS

Others are looking for free open source alternatives of following apps:

Ad Blocker

Ad Blocker is a browser tool that removes intrusive ads and pop-ups from web pages.

AdGuard DNS

AdGuard DNS is a DNS-based service that blocks ads, trackers, and malicious websites.

AI & Machine Learning

Free open-source AI & machine learning tools.

Acorn 7

Acorn 7 is a Mac image editor for editing photos and creating graphics.

AdGuard

AdGuard is a cross-platform ad blocker that filters web content and protects privacy.

Adobe Premiere Pro

Adobe Premiere Pro is a professional video editing software for film, TV, and web.