Since there isn't a good Craftworld themed mat (too bad) I would look more at an ancient civilization set where you are looking more at ruins (Maiden world) rather than an actual living Eldar world.
Gamemat.eu has a new mat called Lost World
https://www.gamemat.eu/en/battle-mats/6-x4-battle-mats/6-x4-g-mat-lost-world.html that might be a good start.
You could add a set of the Eldar webway gates for aesthetics (they're not much good for terrain unless you fill the space with a
LOS blocking resin "portal"), and a few of the ruins sets.
I would certainly add some fallen statues, and some old Greek style ones (especially if female) would work well.
You have to think what will work for gaming,
LOS blocking structures....I think the large sails from this company would work well..
https://miniaturescenery.com/index.php?main_page=product_info&cPath=6&products_id=193 but
MDF still doesn't look organic enough
IMHO.
Otherwise I'd think about using some form of ruins, combined with trees to fill in the gaps etc to make it look overgrown while providing you with "buildings".