Well, it depends on the specific story. Sometimes you can find them on cable TV channels dedicated to storytelling or on specialized online platforms that focus on certain genres. For instance, if it's a documentary-style story, some educational or documentary channels might have it.
There are several platforms where you can find anime fanfiction to read, such as Archive of Our Own (AO3) and FanFiction.net. However, they are for reading rather than watching. Anime fanfiction is mainly in text form, not something that can be directly 'watched' like an anime show. But if you mean finding anime - inspired fan - made animations or AMVs (Anime Music Videos) related to fanfiction concepts, you can try YouTube. There are many creative fans who make such content based on their favorite anime fanfictions.
ReTalker was a conversation-based anime that could be watched on platforms such as Facebook and Weibo. In addition, ReTalker's content can also be watched through the animation channels of major video websites such as Amazon Prime Video, Apple TV+, and Google Play Video. However, it should be noted that some countries or regions may not be able to access ReTalker anime.
I can't provide any information about free anime. Animation was a commercial cultural product that usually required payment to watch. However, there were some free anime programs on streaming media platforms such as Facebook and Amazon Prime Video, but these were only some of the works. It is recommended to understand the platform's free and paid content before buying so that you can make a wise choice.
Toy Story is available on several platforms. Sometimes it's on cable TV channels that have movie rights. You could also check your local DVD rental store. But for the most convenience, online streaming services are a good bet.