Baader–Meinhof Phenomenon
Also known as: Frequency illusion
An object that has just come to someone’s attention suddenly seems to appear with greater frequency. We might get a false view of the frequency of that thing, just because we’re now looking for it. Alternately, we might have often overlooked that thing before, because we weren’t looking for it.
Examples
The reason for this is our brains’ prejudice towards patterns. Our brains are fantastic pattern recognition engines, a characteristic which is highly useful for learning, but it does cause the brain to lend excessive importance to unremarkable events.
You buy a new car, then suddenly see other cars of the same make and model everywhere you look.