Fossify Gallery (fork of Simple Gallery), Fossify File Manager (fork of Simple File Manager) and Fossify Calendar (fork of Simple Calendar) are now available for download on F-Droid.
(Simple Mobile Tools suite was acquired by an Israeli adware company)
About Fossify: Fossify is all about community-backed, open-source, and ad-free mobile apps. A fork of the SimpleMobileTools, which is no longer maintained, and we’re here to continue the legacy, bringing simple and private tech to everyone.
Can not find it in f-droid app repository.