I've bought bulbs for elderly relatives in the past, nice to have something that grows up through winter to early spring, and the pot can be reused if inclined.
I've just bought my mum some cashmere gloves from Uniqlo, using a new email address got me £10 off, making them £15 (and I filled a basket for myself as well, which if I keep any of it, DH can give me for Xmas).
I've also bought bird feeders for my parents in the past too. My personal favourite is the one that sticks to a window, so birds get really close to you. Loved it so much, I now have one on my bedroom window, and love watching the blue tits and coal tits pecking away to find their favourite sunflower seeds!
My mum was delighted one year when I bought her a book that I'd loved (Life After Life by Kate Atkinson), she also loved it, and was pleased to be introduced to an author she'd not read before - she went on to read her other books. She loves it when she can devour a new author.
[My parents suggested adults have a £10-£20 limit on gifts - they're very comfortable, as are we, but as we all tend to just buy what we want, a smaller budget meant more thoughtful gifts rather than a prescribed I'd like x,y,z please. Plus if it's not really your thing, it's not lots of money wasted]