Toki Pona is a constructed language created by Sonja Lang in 2001. Known for its small vocabulary of about 120 to 130 words, the language is designed to be simple and focuses on basic concepts. Despite its simplicity, many people attempt to write about complex subjects using Toki Pona, such as Russian history, Sikhism, the Welsh language, and Attack on Titan.
The official Toki Pona Wikipedia was removed in 2009, but an unofficial version called Wikipesija exists with over 2,000 pages and 16 active editors. If an official Wikipedia for Toki Pona were to be created again, it might be found at a URL like http://tok.wikipedia.org/wiki/lipu_open/ and would be listed under active editions on Wikipedia's language list. You can check out the unofficial Toki Pona Wikipedia here and the list of active Wikipedias here.