Those of you who have taken videos with DSLRs and professional camcorders have probably dealt with shotgun microphones. They are great for doing interviews and YouTube projects in general. There are plenty of standard mounts available for shotgun microphones (some professional camcorders ship with one integrated). These 2 pistol grip mounts are handy if you want to operate your microphone with one hand:
Rode PG2 Pistol Grip ShockMount for Shotgun Mics: this supports microphones with a diameter of 19-20mm or 21-22.5mm using its interchangeable mounts. It offers cable management and easy adjustments.
WindTech PG-95 Pistol Grip Shotgun Mic Clip: an affordable accessory that makes handling your shotgun microphone with one hand easy. It is compact and lightweight. It can be attached to standard mic stands.
Pistol grip mounts are not for everyone. Some folks prefer other types for their projects. But it is nice to have the option of using these once in a while.