If your thing is My Little Pony then sites like Derpibooru are what you would be looking for. Booru type sites offer quite the assortment of settings and ways to post your artwork, along with various formats supported like mp4 and gif styles. Sites like these also offer settings to filter out any unwanted tag that you would not feel comfortable watching on your feed.
That being said, Derpibooru is one of the most well known sites offering My Little Pony works by fans, which vary from safe to watch all the way to NFSW territory and even some other more disturbing works like "grimdark," which is a word used in the site to cover gruesome works including gore and such unsavory themes. There are also other themes such as Involvement of underage characters in sexualized ways as well as other graphic depictions.
Fans should be wary of such themes if they are to create an account to to browse what the site offers, although I will state that you can pretty much find other nicer works by artists who submit wonderful art staying true to the theme of the cartoon shows. The site also offers a voting system where you can either up or down vote any submission displayed, as well as blocking it from view if you don't wish to see it again in future visits. Lastly the site also offers a favorites system to collect any submission you favor, as well as an anonymous setting used to both upload and comment on the site itself, keeping anonymity should you wish it.
It is also unfortunate that while it supports quite a number of rules and guidelines, some members and staff running the site often act in a horrid childlike manner to others, many using the anonymous setting to do so and taking advantage of it. Reports at times are ignored, at times scolding you for even bothering in doing such things and make it seem that if you are too sensible then perhaps you should join something else, which does not look pretty professional in the least.
The site also suffers from glitches like login issues, but other than that technical problems are quite minimal. If you plan on creating your own gallery to store My Little Pony related submissions, then this could be one of the options you would seek, although there are other places where you could be treated better.