I have described myself as a jack of all trades, master of none (even though I've probably mastered some, the second part is so I don't come across as a jerk). I've also used the analogy of having a wide-spread skillset like a decathlete, where I'm pretty good at a lot of "events" but not great at any, and in the end it can be really beneficial to be sort-of good at a lot of things. I actually was a decathlete in college, so that is an easy analogy for met to make and apply to real life. You probably won't do yourself any favors just pointing out that you are good at everything or know everything, even if you really are good at everything or know everything.