It’s nice to mix something with mushrooms, so that it’s less mushroomy. I didn’t try this one, but it seems nice.

https://wallflowerkitchen.com/creamy-leek-mushroom-pie-vegan/

Here is another one, also didn’t not try but I did a few pie recipes from the BBC food sites and they were great:
https://www.bbc.co.uk/food/recipes/mushroom_ale_pie_90722

Google vegan mushroom galette

https://herbivoreskitchen.com/2020/09/savory-mushroom-galette-recipe/

You can always add stuff, but this starts off dairy free.

Something like this?
https://www.theguardian.com/lifeandstyle/2009/dec/12/mushroom-tarragon-pithivier-recipe

You could add some flour to thicken the sauce and leave out the creme fraiche, to skip the dairy component.

I want to make some kid of mushroom pie/tart/galette....

I need it to be DAIRY FREE. I can use eggs, but I don't want a quiche. I don't want fake cheese but can use a plant based butter.

I'm thinking maybe puff pastry, since that's easy to get dairy free, but I'm happy to make a dough too.

Anyone have any favorites?