Okay, here are just a few initial thoughts for people with vegan DDs or girlfriends to buy for - these are all good brands, varying in price, which I will indicate.
The Ordinary - mostly vegan, can be hard to buy for another person’s skin, though! I recommend the rosehip seed oil as a starting point, but if you know DD’s skin concerns, could be more specific. [Affordable, but modern/not a bad gift]
Glossier is mostly NOT vegan but does label the vegan products clearly on each product page. The milky jelly cleanser is usually vegan, and some shades of the cream eyeshadow (Skywash) if you want to give Glossier gifts. Also the lip gloss is all vegan!
Cloud Paint is not vegan! [Expensive but not 'luxury']
Le Labo is entirely vegan and cruelty free.
Hourglass - all their brushes are vegan. Their makeup products have now all been reformulated to be 100% vegan (most already were) but it is conceivable some older non vegan ones might still be in (eg) TK Maxx. Good options are the blushes, powders, ambient lighting palette, primer if DD uses it, mascara, brushes, lip oil. (Their products are v pale and some American customers feel the brand is racist, so anyone with DDs very deep in social justice culture might want to avoid, and it’s maybe not the best for women with deeper skin tones if it may look ashy.) [Luxury low end]
Malin & Goetz - all vegetarian, not all vegan. Vegan products are labelled on the product page on their brand website. [Luxury low-end]
Aether Beauty - all vegan. US based but I originally found it via them being stocked in Free People, so clearly they are importing a bit! ['Clean' beauty / niche brand / mid end]
Charlotte Tilbury is a mixed bag and it can be hard to find out for sure if something is vegan. But she does have vegan products, it’s just not an ‘easy win’. Some of the big name lipsticks and blushes are definitely vegan, and you can get vegan concealer & foundation for sure (you’d have to know DD’s shade match!). [Mid end]
Happy to clarify vegan status of anything if I can be helpful at all :)