Baader-Meinhof Phenomenon
Also known as frequency illusion, the Baader-Meinhof Phenomenon is when something you've just noticed, experienced or been told about suddenly seems to crop up constantly. It gives the feeling that out of nowhere, pretty much everyone is talking about the subject, or that it is rapidly surrounding you.
The Baader-Meinhof phenomenon happens due to two cognitive biases: the selective attention bias which directs your brain's attention to things that align with your current state of mind, and the confirmation bias where your brain loves to prove its own views and hypotheses. These biases create an effect where something you've just noticed suddenly seems everywhere. A clear example could be when you buy a new car, and then you start noticing that particular car model on the road wherever you go.