A curated collection of tools to aid transcriptionists and subtitlers.
While all subtitle formats can be handled by the Subtitle Edit application also listed here, Aegisub specifically focuses on the Advanced SubStation Alpha format. So, if you only plan on building Advanced SubStation Alpha scripts, you may consider using Aegisub as an alternative because its GUI is specifically designed with ASS in mind and brings all of the ASS-specific options right to the forefront, as well as comes with ASSDraw to aid in designing vector images which can be included in your scripts.
Aegisub
https://github.com/Aegisub/Aegisub/releases
FontBase allows you to quickly load and unload only the fonts you want when you want them, without having to actually install any of them. This allows you to more effectively manage your resources when working with large collections of fonts, such as Google Fonts. You can also load individual fonts or folders of fonts, or watch folders of fonts if you are actively adding and/or removing fonts from a given font folder.
FontBase
https://fontba.se/
Google Colab allows everyone free and instant access to a high-powered cloud-hosted virtual machine with a templated environment ready to go and specifically optimized for Python AI projects.
Whisper
Whisper is OpenAI's speech recognition system, which is the upstream repository upon which most other such projects are forked from or based on somehow, and is still paving the way for much of the cutting-edge development in the space.
Whisper-diarization
Whisper-diarization is a much more advanced speech recognition system using the more accurate and faster whisperX system instead of the original whisper system, and also comes included with diarizaton for identifying speakers.
Google Fonts are a go-to for anyone needing free and open-source fonts since they have a huge selection to choose from, are the most popular font collection used on the Web, as well as are the native fonts used by Android, so basically everyone is already familiary with them in one way or another.
Google Fonts Website
The Google Fonts website provides a nice front end to the Google Fonts collection, with browsing and search capabilities based on a number of criteria.
https://fonts.google.com/
Google Fonts GitHub Repository
The Google Fonts GitHub repository is where the actual magic is happening behind the scenes in the curation of the actual fonts themselves. You can either clone the repo with git or grab the master.zip and instantly have all of the Google Fonts at your disposal on your local machine.
https://github.com/google/fonts
This is not FOSS, but the free version has everything you need to quickly and easily trascribe any audio or video file. It's a nice, clean, streamlined application with a small footprint, so transcribing even large media files on machines with quite limited resources is still quite a smooth process with this. The only slight annoyance is that you cannot save directly from the interface in the free version. However, since this is not a word precessor anyway and not good for things like spell-checking, etc., you will probably want to manually periodically cut and paste your work into a word processor anyway and save your work through the word processor application (Microsoft Word, LibreOffice Writer, etc.).
InqScribe
https://www.inqscribe.com/
FOSS office suite of applications. If you were ever worried you might have to buy Microsoft Office to get work done and collaborate with others sharing Microsoft Office documents, think again!
LibreOffice
https://www.libreoffice.org/download/download/
This is a nice lightweight media player that works with Avisynth and FFmpeg pipes out of the box and is much more streamlined than VLC, so a great minimalistic media player if you want a GUI that's a bit more extensive than FFplay but not as resource-intensive as VLC.
Media Player Classic - Home Cinema
https://github.com/clsid2/mpc-hc/releases
A nice little open-source font viewer that lets you sample fonts using any text you want, and especially great for if you need to quickly sample through a lot of fonts. If you're wary about downloading the installer executable, just get the portable .jar Java file instead and it should work as is as long as you have Java installed on your machine.
Opcion
http://opcion.sourceforge.net/
As the name suggests, this is a great subtitle editor to quickly and easily put together or convert substitles for a variety of subtitle formats.
Subtite Edit
https://github.com/SubtitleEdit/subtitleedit/releases
You probably already know what VLC is, but I am just including it here for completeness since it can easily be part of any AV workflow. You can also pipe FFmpeg directly into VLC just like FFplay and it can serve as a more robust replacement.