Stereo microphones are really two microphones in the same case, this allows recording of sound to two separate channels.
Dynamic microphones have the advantages of being relatively inexpensive and hardwearing as well as working independent from an extra power supply. Condenser microphones are generally geared to high-end professional sound recording.
This refers to the way a microphone transmits signals. Wireless will afford extra freedom, but not all models come with a transmitter and receiver that is needed to transfer the signal.
There are three types of polarity, or the ability for the microphone to detect sound in a given direction. Unidirectional is for a single source of sound. Bidirectional microphones allow equal detection from the sides, but not detect well from the very edges. Omnidirectional refers to general detection of sound from all around, as from an entire room at once.
Polarity
Cardioid, Supercardioid, Shotgun