Find the elf. Keep track of where it goes.

@Zaku I do something similar. I feel awkward doing so.
Also sometimes I just stare at the host.

It’s a really good question. I’m sure many people feel some version of the same way, when they are not actively engaged by someone, or doing something.

It’s not inappropriate to look at other people, but in a small group, say, where they or others may notice you staring at a particular person if you do it very long, that could become inappropriate. If the space and group is large enough, such that it won’t draw attention, it may not be inappropriate to stare at others, even for some time. It helps if you have a socially acceptable reason for watching a particular person, but in a social gathering where there’s not much else to do, it can be ok.

Developing ways to entertain oneself (or others) while hanging out in a space is a facility worth developing.

Besides looking for elves, or watching other specific people, or introducing oneself to and talking to other people, it can also be entertaining enough to watch and reflect on group behavior, or find a group with jabberers that seems open to more listeners, or checking out objects/art/etc that may be on display in the space, or exploring the space. Of course, there’s also bringing companions along to keep one company and jabber with.

You might even try locating other people who seem unoccupied, introducing yourself and/or asking them idle questions, or reflecting on observations you may have (that seem socially acceptable to bring up to a stranger . . . though some people seem to make a point of choosing unacceptable things to talk to strangers about – your mileage will vary with that one, depending on what you say to whom, and how).

I just go sit quietly somewhere by myself and look around and Think Things.
Somebody always shows up to engage me.