This pdf lists lots of Chinese Sutta Nipata parallels, most of them not yet listed on your site. The intro is in Japanese but you don't need Japanese to understand the index.
Yajima, Michihiko (矢島道彦)
„Suttanipata対応句索引“ [An Index to Parallel Verses and Padas of the Suttanipata collected from Buddhist, Jain, and Brahmanical Texts]. - In:Bulletin of the Institute of Buddhist Culture, Tsurumi University. - 2 (1997), 1, S. 1-97.
URL: http://ci.nii.ac.jp/naid/110004777657 (CiNii)
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