4 A Reliable Tripod/Mount
Image via ARMOR-X
Yes, they make tripods and mounts for the iPhone, and they are particularly effective when taking longer, professional videos that require some setup. Image stabilization is always a notable issue when capturing video with a phone, and while software can help, nothing is better than a good mount accessory.
The ARMOR-X tripod, for example, includes excellent bendable legs that can grab onto fences, branches and bars so you can get whatever shot you need without worrying about positioning.
If you do a lot of handheld iPhone work, such as walk-and-talk scenes, then you may prefer a LanParte gimbal for active stabilization when you are on the move.