If you have a clubcard, tescos have loads of gift sets reduced in clubcard price!
For some budget things:
Home bargains have some nice little sticking fillers, including alcoholic gifts, games, socks, toiletries etc. They also do lovely Christmas mugs & gin glasses for £2.49. A friend of mine also likes their large candles which are £2.99 (the vanilla one seems to be popular with loads of people).
B&M have some nice chocolate/biscuits gift sets, a big friends section if you have a friends fan. They also do initial mugs & coasters. They have mini games like say what you see & Mr & Mrs for a couple of quid.
In my stockings so far:
Keyrings, socks, mugs, chocolates, face mask (for pampering), face coverings, lynx for the blokes lol, nice shower gel gift sets, hand cream, diary etc.