I don't know if you can expect to find unity-specific examples of interview questions anywhere. In general, the team will probably put you through a few design or thought exercises, have a technical discussion with you, and probably have you do some whiteboard coding or code critiquing. Advice for all of this, as per general, is relatively well known -- listen, repeat, clarify before attacking a solution, think out loud, and do not hesitate to change directions on your solution if it seems you've got stuck -- I've failed one interview by looking for a log-N solution that I was sure existed (and it did) but was more complex than I imagined, and because of complexity was actually no faster than the linear solution that was obvious. If you think you need to backtrack, its actually an excellent time to bounce ideas off your interviewer -- "I went this way because X, but now I see Y. That makes X hard, but maybe Z is a better solution. What do you think?" They're not going to give you the solution, or probably even tell you whether they'd choose X or Z, but they will almost certainly help you puzzle things out some more, and its not the kind of thing they'll dock you for if you are going about it intelligently. They aren't looking for people who know the solution to every problem cold, they're looking for people who can find solutions to problems they maybe haven't seen before.
Practice questions -- even or perhaps especially the non-technical ones. The goal isn't to come up with a script, but ask yourself the questions and write down the answers. The goal is to simply bring relevant information from your experiences to the top of your mind. You don't want to wake up the next morning regretting that, under pressure, you failed to recall that really great story you have about solving a similar problem.
And as per usual, I will recommend you to buy and read "Programming Interviews Exposed" -- its in its second edition last I looked, and the best $30 a programmer can spend. It covers everything from resume tips, to typical soft and hard questions, to thought exercises, to how to dress, to how to negotiate a salary. Buy it now.