Love this question...
Sunday Riley Autocorrect eye serum - have repurchased this a couple of times.
Lumene Nordic-C Valo Glow Boost Essence - basically a Vit C Serum. This came from my first ever beauty advent which was John Lewis 3 or 4 years ago. I've bought the Lumene advent calendar this year because this is in Day 25 and alone it covers 2/3 of the cost of the calendar - I managed to bag a discount.
Tatcha Dewy Skin Cream - love this so much!
Biossance Squalane and Vitamin C Oil - my skin loves this and it isn't too oily.
Like a PP I also found Alpha H liquid gold in an advent calendar and always go back to this for exfoliation.
Controversial but I actually like the Augustinus Bader rich cream too...although wouldn't repurchase because it's too expensive.
To be fair I rarely re-purchase items because I have several calendars each year (have Space NK, HNs, Lumene and Sephora this year plus the Space NK fragrance) and I buy beauty boxes when I know the value of the products I will use or would like to try outweigh the cost so I rarely need to re-purchase specific items as I have quite a large stash fairly constantly. I recoup some of the cost of items I won't use on Vinted too or use them for gifting.
Interestingly I find I do 80% of my beauty purchasing at this time of year as this seems to be when the best offers come out and obviously the advents which are insane value for money if you will use enough of the products and can sell the remainder. Threads like this are invaluable 🙂