I am planning to play Morrowind for the first time.
I will be playing using OpenMW on Linux.
What shall be the basic graphics improvement and quality of life improvement mods that will be compatible with OpenMW?

Thanks in advance.
:)

There is a specific wiki on this:

https://wiki.openmw.org/index.php?title=Mod_status

And several forums:

https://wiki.openmw.org/index.php?title=Mod_status

For a first-timer, just use these quality of life mods with openmw:

Patch for Purists: https://www.nexusmods.com/morrowind/mods/45096
Better Expansion Implementation: https://www.nexusmods.com/morrowind/mods/47068
Official Plugins: [url=https://en.uesp.net/wiki/Morrowind:Plugins ] https://en.uesp.net/wiki/Morrowind:Plugins [/url]
Unofficial Morrowind Offical Plugins Patched: https://www.nexusmods.com/morrowind/mods/43931

Thanks for your responses. Would I need to install Official Plugins even if I install UMOPP?

No, just UMOPP is sufficient. "It's recommended to use Unofficial Morrowind Official Plugins Patched instead of these." - https://modding-openmw.com/mods/bethesdas-official-plugins/

I only use Morrowind Graphics Extender just to get 1080p and Greater Draw Distance to remove that "Fog of War" look.

Morrowind is one of the few games I am content to play Vanilla gameplay wise.

Unless someone has made an original content for Morrowind on the level of that New California Mod for Fallout New Vegas. Or Nerhim for Oblivion.

Like these?
https://sureai.net/games/arktwend/
https://sureai.net/games/myararanath/

Morrowind ... It's been a long time. I remember the Less Generic NPC Project and Morrowind Comes Alive which added new unique dialogue to NPCs and created NPCs in different places.