Here is the list of  Plagiarism checking software (Free/proprietary)

1. Urkund by OURIGINAL (Proprietary software)

2. Viper (Free software): Viper is another plagiarism checking software, which has been used to scan 10 million resources as claimed in their website.

3. Plagiarism detector (Free software)

4.  Plagirisma.Net (Free online checking).

5. Copyscape (Online Free Plagiarism detecting software)