If you choose to use a USB microphone, you don't need a lot of equipment for ASMR videos. However, if you go with a studio microphone, you'll need an XLR cable and audio interface. Microphones sensitive enough to provide excellent audio for ASMR will also be sensitive to any vibrations or physical movement like footsteps in the room. A shock mount can be an excellent investment to avoid these unwanted noises. The cat's cradle or spider mounts, as they are known, are the most popular and provide excellent physical isolation from vibrations.  Depending on the type of content you're making, a pop screen could be beneficial and an inexpensive way to get rid of unwanted sibilance from your recordings. That said, some creators emphasize these same consonants to great effect.