One of my most reliable warm-ups, I was able to present this at the SDC in 2022.  Rather than just asking people to see if they match, students are encouraged to ask questions about the subject (Restaurants is the most frequent topic).  

Applicable for many lessons, we even used it to practice grammar points.  In general, students are expected to ask 3 questions before they can show their card.

It becomes quite a wild activity that ends with a lot of excited screams when they find their friend is their partner.