Here are a few tools that i've been using lately that I really enjoy:
https://pocketbase.io/ - A dead-simple self-hosted firebase/supabase-like "backend in a box" using golang and sqlite. So far i've been really impressed. I've gone the route of extending the base offering with more go code and am really enjoying the experience.
https://excalidraw.com/ - An open source whiteboarding tool. Slick to use and after learning some keybinds I've gotten pretty fast at throwing together diagrams to explain things to people on my team. The killer piece though is that the filetype is just json, so I can source control my diagrams. Even better, their "export to png" function has a box to embed the json data _into_ the png, allowing me to slap the diagram in places that only accept images (think confluence) and still be able to change the diagram later if needed. 10/10.
https://docs.gitlab.com/ee/ci/ - Gitlab's CI/CD toolset is really impressive, and I've gotten really intimate with it's deeper features over the past year. I'd be curious though to hear from someone who's familiar with it vs it's competitors. The only other CI "platform" i've used (barely) is Github Actions, which I didn't like off the bat.
I'm a fan of WSL (Windows Subsystem for Linux), which allows me to have Ubuntu on tap at any time on my Windows 10 machines. I also like Virtualbox for running older systems like OS/2.
On my phone, I use Termux, and SimH to carry around a VAX 11/780 running VMS 7.2
When it comes to DSP, I find that GNU Radio works well enough to do experiments with Software Defined Radio.
Across everything, GIT is one of the best software tools since the days of PKzip files on floppy disks for keeping a handle on source code versions. I push everything to GitHub for backups.