I've got two - Aegean Airlines in the Mediterranean, which was called out above as well... great food and service in Y on a few flights that I did as a part of a status match with them many years ago.
The other was IndiGo in India, for some short hops between BLR & HYD that I'd done in the couple of years prior to COVID. A budget carrier in India, and even so, it was a clean, comfortable and efficient from check-in to arrival. Glad to see they were the choice for QF on their newer codeshares inside India, though I'm still more likely to connect through Asia (SIN/KUL) than fly direct to BLR/HYD.
Cheers,
Matt.