There are a few games on the site that can be played (in some cases exclusively) in the constructed language Toki Pona, but currently it's not possible to select it as a language for a game in the metadata section of an upload, or to browse via language code. Toki Pona now has an official ISO 639-3 code ('tok'), so it would be great if it was added to the list - currently a game that's playable in English and Toki Pona either has to leave the language metadata blank or in a misleadingly incomplete state.
ISO 639-3: https://iso639-3.sil.org/code/tok
Examples of games currently using the toki-pona tag: https://itch.io/games/tag-toki-pona