Get to know them, visit them. Video call them. And then ask them yourselves!
I should be grateful that people want to make the effort, but burdening my already heavy mental load by asking me to find something that they can buy online in a few clicks isn’t really much effort. We really try to not to over-consume and buy our toys secondhand. I’d rather they didn’t send anything at all.
There is one relative who makes a huge amount of effort to spend time with them and she finds out herself from them what gifts they would like.