Paintless Dent Removal, as the name suggests, is simply a paintless dent removal process. However, as anyone who enters the industry finds out, the proceess is not as simple as it may seem. Specially trained technicians who undertake a program of PDR training are taught specific skills to push dents.
The PDR industry has progressed significantly since the early days when the common table spoon was used to push dents to avoid re-painting luxury vehicles on the assembly lines in the 1940 era. 
As the images here illustrate, the set of available tools developed in the last 60 to 70 years is rather extensive. A typical tool kit range from the access and reach bar collection to glues and bits.