It's possible that:
* Her information is limited online: There might not be extensive English-language resources detailing her filmography.
* She may be more prominent in Japan: She could have a strong presence in Japanese television and films, but her work hasn't crossed over to international markets.
To find more information:
* Search Japanese movie databases: Sites like Japanese Movie Database (JMDb) or Allcinema might list her projects.
* Use Japanese-language search engines: Try searching for her name in Japanese (初音 ことえ).
Please keep in mind that it's difficult to give a definitive list without more specific information.