I love silly presents, whether I'm giving them or receiving them. I very rarely give to charity on somebody else's behalf, since it can all too easily be seen as a form of virtue-signalling, but occasionally do so for wedding anniversary celebrations, for instance, if people have said explicitly that they don't want presents. In those cases I will often give a wee potted cyclamen or similar, along with the card.
My requirements for a good 'silly' stocking filler are that it should be small, inexpensive, and most importantly should be something that the recipient will enjoy receiving, and not a tease. I wouldn't give someone sugar tongs if I knew they had diabetes, nor an egg cup to someone who I knew didn't like eggs. But I have given crystal growing kits like the ones you can but as gifts in the Science Museum gift shop, paper flowers that will open and 'bloom' in water, a mini Zen garden with sand, miniature rocks and s tiny rake, or a mini Stonehenge to build, or cracker-sized puzzles (15 tiles to fit into a 4x4 square etc). In practice I only give silly presents to people whose tastes I know, because I don't want to risk hurting their feelings. Mind you, that can be hard. I'm much too old now to be offended if I get toiletries, but when I was younger and had less confidence. I used to be afraid that they had been given as a not-do-subtle hint, but now I appreciate them, even if it's only because I don't have to think about where to put them, or about having to display them prominently when the giver comes to visit!