Collectable items can be a nice idea for gifts. My mom used to give the kids an engraved ornament each year for Christmas, with the year and their names engraved on them. I thought it was pretty cool. There are lots of other collectable items or collectibles available too. Some people collect salt and pepper shakers or blown glass figures, etc. I like adding to someone's collection. It doesn't need to be anything big or super expensive, but I think it's a nice, thoughtful gift, if I can find a special item to add.
I am not a collector, so I don't really appreciate it when someone decides I need to start collecting things, but if someone has already started a collection they enjoy, it really makes giving them gifts much much easier as I have some ideas of what they would like. It really depends on the person though, as sometimes just adding to their collection can look like you weren't really trying.
That is a good point, Dancinglady. I guess if they just grab whatever because it fits the theme, that would be kind of lame. I try to make sure it's something they don't already have and that they would like. For example, someone I know who collected blown glass items, always wanted a bunny, but with a particular look. It actually took me a long time to find one, but I was excited when I did. The good thing was that I knew what to look for, and otherwise this person is hard to shop for. Yeah, "forcing" a collection on someone would be a bad idea, lol.