I do as well - a tablet got stuck in my throat when I was younger and since then cant take anything too big.
Vitabiotics Vitamin D are tiny as are their vitamin B (which I just ordered because of this thread lol)
I have a multivitamin that's a gummy - they do adult versions of these now - im not sure how good they are really and they do have sugar in but they are an option
Also Better You sell sprays - they are on Amazon, Holland and Barrett - they do a vitamin D spray, multivitamin, vegan vitamin and a few others I think - all quite good!
I've just ordered the Floradix Tonic recommended on this thread too which is a liquid and looks quite good for vitamins plus iron