Fanfiction.net - This website has a large variety of different fanfictions, not only to Hotarubi no Mori e, but to many other great anime series' as well! I took a look at a few of these fanfictions, and they are all great! Each fanfiction lets you know what it is rated, what language it is in, what type of fanfiction it is (ex: romantic, horror, comedy), and how many words there are in each writing piece. This website is very reliable and will give you a good taste. Just click the link to the left and you will be directed to the fanfiction for Hotarubi no Mori e. Enjoy your reading!
Asianfanfics.com - Another website that has a large variety of different fanfictions. This website is a little bit harder to find things you are looking for, but they do have some Hotarubi no Mori e works. If you are looking for great stories, here is a good place to go. Just be prepared to do a little bit of digging around! Who knows, maybe you'll find another set of fanfictions you'll love on the way. Enjoy your reading!
Animespirit.com - This website is in spanish, but if you have googlechrome or another way of translating the fanfiction, they are great stories! The link will direct you right to the Hotarubi no Mori e section of the website! This website tells you when it was last updated, how many chapters, what genre the fanfiction will be, and a brief description of the fanfiction. Enjoy your reading!