There are two items that have proven to be invaluable in my endeavors as a news/documentary shooter: clamp and table top tripod. These two items allowing me to take my light and microphone off camera when shooting solo. Together, I called this my mobile grip kit.
The clamps I use is the Manofrotto Nano Clamp. The Nano Clamp has a range of 13-35mm which is small enough for camera/grip rods and large enough for most doors. It has a ratcheting knob for maneuvering tight spaces and it is solid metal except for the pieces of rubber taped to the jaws to protect the surface it clamps too. I found it still mars surfaces if you clamp too tight. I recommend dipping the jaws in a couple coats of Plasti Dip instead. Operation is not as fast as the spring clamps but the versatility and strength for the size is unmatched.
As for the table top tripod, I prefer is the V-Pod-S. The main selling point is the legs which wrap around a removable and extendable center column providing a height range of 6-36mm. To achieve the minimum and maximum height involve changing the leg angle by twisting the center ring which is a slow process. I usually leave mine at the lowest angle for maximum stability. I have tried numerous other table top tripod but found this to be most versatile.
I pair these two items with a ball head and/or a cold shoe adapter allowing me to quickly put a small light or microphone close to my subject as oppose to on my camera.