The new 0.1.13 release of ZLEqualizer works in Ubuntu 22.04 and possibly older versions.
It was far from obvious how to actually use it and the buttons don’t have any tooltips to indicate what they do, either. So may need to spend some time figuring out how it works.
If you look here [ZL Equalizer | ZL Audio]
You will find a simple instruction manual
p.s
It now works with current AvLinux MXe
Since today, ZL Equalizer is available in the openSUSE proaudio repo !
thanks Robin, I didn’t have this link https://linuxsynths.com/
but I did have these others:
https://www.audiopluginsforfree.com/linux/
https://wiki.linuxaudio.org/apps/start
And in this link there is a list of (2019) various audio software for linux->>>Exhaustive List of Free Native Linux Plugins - LinuxMusicians
I have quite a few links to pages that have one or more plugins in the Linux version.
I don’t know if it would be interesting to have a place in the forum where you can consult links like the ones we have put in this thread (software lists), or even specific websites that only have some plugin for Linux, and for which new ones appear.
Do you consider the idea useful?
greetings
Check the ChowMultiTool plugin. It has a simple EQ tool “with linear phase and “drawable” capabilities”.
Do you think thata it is better then ZL Equalizer ?
I don’t know. You mentioned you are looking for a simple and open source tool. It is simple and open source and an option you could check if it is fitting for you.
At first sight, no mid/side eqing. As eq it seems more limited then zl even if it is far from perfect. It has automation as weak point 
Then I don’t know. I also miss the EQ10Q and their Compressor plugin.
And unfortunately Linux is really not like Windows that you can quite easily run even 25+ years old vst plugins, even on Linux with Wine.
You can still run 20+ year old LADSPA plugins on Linux.
Of course, they come with their own costs too.
You tried ZamDynamicEQ per chance? It’s really good in my opinion and easy to use.
DeeQ but it’s neither free nor libre.
Yes. ZL eq is now tested and it is good for my point of view.
Yep, not bad but too limited…
there will be reasons why some people spend €170 for Pro-q3
Yes until you need an automation. Sadly only a few parameters can be automated.
DeeQ but it’s neither free nor libre.
Not everything has to be free, but reasonably priced.
Venomode Maximal3 Is a great master limiter/clipper, which I got for a good price through the ADSR online store. Since Venomode makes Linux versions I ended up buying.
Aye I agree completely, I bought both ages ago 
(along with the arpeggiator). For a good number of people though the free/libre thing is important so I wanted to state it.