It looked like it was going to be a lame list geared towards newbies, mostly due to the categorizing, but I thought it was quite a good list and was much more expansive than I was expecting.

It seemed to cover most categories good enough, although someone's favorite tool will undoubtedly be noticed when missing.

Speaking of...not to nit-pick, but one missing one really stuck out to me (LMMS), but I'll slap a few more in a list too:

Music Making Software:

• LMMS formerly Linux MultiMedia Studio, I think they've tried to be more inclusive of platforms since the Windows releases started and shifted towards the name Let's Make Music... or something. Great app that reminds me of Fruity Loops from back in the day. The project has been around awhile and could be called a staple for such a list.
• Rakarrack maybe less well known, but since the list has a guitar amp app, this app is a whole guitar FX stack.

Virtualization:

• lxc/lxd - Linux Containers light containers, similar to Docker, but also support for full VMs (in lxd at least).
• qemu - It's hard to see a Linux virtualization list not mention qemu. and some front ends like AQemu and virt-manager.

Browsers:

• Libre Wolf is a privacy and freedom focused fork of Firefox.

IDE Editors:

• Arduino seems appropriate for this list.