Best open source tools

An open-source spectrogram viewer

An open-source Android companion for supported watches, bands and other devices

A command-line multi-system emulator with input remapping

An open-source email client funded by user donations

Arrange PDF pages with a graphical thumbnail interface

A Nintendo 3DS emulator based on Citra

Independent XR browser with documented tracking controls

Publish or open EPUB reading through a web browser

PDF content and page editing with browser and desktop routes

Free online chess, analysis and collaborative studies

A customizable comic viewer derived from Comix

An open-source launcher for Epic, GOG and Amazon libraries

An audio-programming system for instruments and effects

Community tablature editing with tab and MIDI imports

Open-source gamepad-to-keyboard and mouse mapping

Tile and filter PDF sewing patterns before printing or projection

An open-source player with a modular web interface

A multichannel sampled-drum instrument

A shared interface for emulators and game engines

Native-format timeline editing with capture and monitoring options

Pattern-based live coding for algorithmic music

A cross-platform ebook library with synchronization options

Cross-platform backup and restore for PC game saves

A dedicated application and library for H.264 video encoding