We added several shelves in this house using “drive” type molly anchor bolts. Later we decided to remove the shelves, but this left a problem. The “leftovers” are quite difficult to remove without creating a “hole in the wall.” I discovered a simple way to remove them.
At first I tried to place a screwdriver or nail inside hole of the molly and tap in gently till it pushed beneath the surface of the wall (then cover with drywall compound). This worked sometimes, but it still did not look correctly.
Then I found that a pair of needlenose pliers worked better…
ISO M20 Trapezoidal Thread. Based on information from https://mdmetric.com/tech/thddat16.htm.