Asklemmy

Hard to answer but maybe Haiku or GNU Emacs

Linux, Firefox, OBS, Emacs, Hatari

Neovim. It's an awesome editor and it has a great community and ecosystem.

Suricata

QGIS and OpenStreetMap for mapping

vim

I’ve been liking Digikam and Rawtherapee (which is an awful name for the record) for photo gubbins.

Currently OBS and Motrix

Linux, Tor, and the Ballistica game engine/BombSquad game (not fully open source as stuff used for sensitive data remains closed source 😔)

Edit: forgot git lol

Definitely OpenFOAM. It competes with commercial software that costs thousands of dollars.

For games:

• Anuto TD (found a few days ago, isn't super feature rich but still fun to kill time)

• Mindustry (never played a game like it before, ended up supporting by buying it on Steam)

• Supertuxkart (I love how many custom add-on karts and tracks I have)

For non-games:

• Termux (allows me to get apk files and install Revancify for add free yt)

• VLC (I don't mind slow updates and have yet to switch mostly because I can't find anything better that isn't more complicated than it needs to be and/or is closed source)

• KDE Connect (I have almost always had problems with moving files from and to my desktop via cord)

I'd include something like Linux, but I personally feel that's kinda cheating because of how large it is compared to the others.

ShareX and it isn't even close

Linux, Firefox, Apache

ReVanced. I love my ad-free, sponsor-blocking, Shorts-removing YouTube experience.

As a bonus, I also enjoy using Mp3tag. It's a program I can use to easily change and update the tags on all my music files, and it can even do it all in batches. It can also connect to various music services (Discogs, Musicbrainz, etc.) to get music tag info directly so you don't have to type it all in manually.