First I'd say you shouldn't feel bad about going by yourself. This is still a work event so you should be able to comfortably go alone. That said, if you feel there's pressure to bring someone and/or that you yourself would be self-conscious if you went alone, here's what I would say: Be very strategic about who you choose to bring. Not only will people form significant impressions of you based on who you choose to bring, but if chosen properly, your guest can be a partner in helping you effectively work the room and advance your goals at the company.
Consequently, you want to choose someone who has broadly effective social skills, and ideally, someone who has worked or socialized with people at companies like yours. You want someone who you can comfortably leave alone as you talk to at other people at your company, as you'll inevitably have to for much of the night, but also someone who might help you approach others who you don't know as well but would like to. And you want to go over with your partner beforehand who some of these people are and how you might approach them.
As to where to find this person, you likely have friends in your various social circles that fit the bill of being socially adept and on board with helping you. A family member like a sibling or a cousin can be a good option if they've got the right skills. I wouldn't bring a parent, though, unless it were some function where you were getting an award or otherwise being honored. And I'd be cautious about bring someone who you're interested in romantically, but are not yet dating -- you don't want to be in a situation where you're more concerned with taking care of or impressing your guest than with working the room. Ideally, once you've identified some good candidates, you'll cultivate them and offer to do the same in return for them in case this comes up again in the future for either of you.
Some might feel this approach to be too calculating or cynical for what seems like a social event, but the fact is, every event with people you work with is an opportunity to make an impression on folks who can help you in our career. You should never forget this, especially during challenging times like now. And needless to say, this strategy of preparing your guest and going over who the important people at your company are certainly also applies if you were in a relationship and were bringing a spouse or significant other.
I once had a client who was a middle manager in a consumer products company who was invited to a company party and wasn't dating anyone at the time. She would up bringing a guy who had very good social skills; he charmed some of my client's colleague's wives, dancing with them and deftly working in references to how much my client loved working at her company. The following week, a couple of senior managers came up to my client and told her about the positive impressions their wives had gained of her as a result of her guest, which helped cement my client's relationship with those managers. My client eventually got promoted, and while I can't say it was all because of this one party and what her guest did for her, it certainly didn't hurt. You should try to choose someone who will be similarly effective for you.
Read More Power Plays From Ron Brown:
Help! My Colleague Is Trying To Sabotage Me
How Should I Prepare For My Performance Review?
Help! My Boss Is Micro-Managing Me!
Help! I Need a Mentor
My Boss Is Trying to Steal My Ideas
Send Ron your career and job-related questions.