There are a lot of clippers out there. Some paid, some free.
StandarDCLIP and KClip Pro are excellent paid plugins; Clipmax and Free Clip are excellent free plugins.
However, the amazing quality of the free ones has not justified the demand for the paid ones, and I can quote Free Clip as a major responsible for this.
After a few weeks of exhaustive testing, at least on the personal criteria of my own audition, I feel comfortable and secure in stating here that Free Clip is top.
Using it for mastering purposes in "Hard" mode, 1x Oversampling and -0.1dB Clip Ceiling, I got the most transparent result I could expect. No other plugin, paid or free, hit Free Clip.
A single lack I felt - the parameter "Gain" could be able to handle negative values. But this absence does not stain the surprising quality of this plugin, since I use the alternative features of my DAW.
Free Clip, with due respect, makes it unnecessary to use commercial alternatives.