Alright, guys, welcome to the Resources Thread! This is exactly how it sounds. Here is a list of links that I and other members find useful to all things writing. Of course, if you have a link that you find useful for writing, go right ahead and post it here and I'll add it.
Pokemon Related:
https://www.serebii.net/index2.shtml - This is the first website I go to when needing Pokemon information since it's quick, reliable and navigable (not including times when it's as slow as hell).
https://bulbapedia.bulbagarden.net/wiki/Main_Page - My second Pokemon resource, this site is useful when I need to know anime stuff, like what an attack looks like and things that Serebii doesn't have.
https://www.trsrockin.com/tales.html - A guide on Pokemon glitches, from the Pokemon to tricks and locations (Glitch City, exc.)
Character Related:
https://www.mybirthcare.com/favorites/babynames.asp - A nice site for getting names when you can't think of one.
https://www.behindthename.com/ - Another site for names, but this one has the history of the name and way more options to play around with.
https://en.wikipedia.org/wiki/Mary_Sue - The most comprehensive guide to Mary Sues, believe it or not. A definition of what they are in general, followed by the basic archetypes and examples.
https://fullcircle.comicgenesis.com/characterdevelopment.htm - Definitely something to look at if you want to know how to flesh out a character and make them feel like a real person.
https://www.poewar.com/get-ready-for-10-days-of-character-building/ - Ten articles on building and fleshing out a character. Includes questions and ideas to help you on this path.
Plotting Related:
https://www.sfwa.org/2009/08/fantasy-worldbuilding-questions/ - Awesome site of awesomeness. It's a great help for building fantasy worlds like you wouldn't believe. Includes questions on geography, culture, history, magic- all that fun stuff.
https://www.writing-world.com/romance/starters.shtml - Ever have trouble thinking up a plot? Then here's a list of ten ways to jump-start that epic plot waiting to be found! It's sot of romance related, but it's still has great advice, so check it out.
https://www.advancedfictionwriting.com/art/snowflake.php - This is more for writing novels then fanfiction, but it can still be used. This is the ultimate plotting guide which will help you on the way to making a strong and structured story.
Writing Mechanics:
https://dictionary.reference.com/ - Exactly what is says (it even has a thesaurus!).
https://owl.english.purdue.edu/exercises/ - A pretty thorough guide to grammar, complete with various exercises that help you develop your grammar-related skills.
https://www.grammarbook.com/english_rules.asp - Another guide that's just as thorough as the above. Includes detailed examples and more details about rules OWL's a bit fuzzy on. (This includes a list of commonly confused words, too.)
https://orangoo.com/spellcheck/ - Online spell checker.
https://www.uky.edu/AS/Classics/rhetoric.html - Goes over rhetoric terms (simile, metaphor, exc.) and lists examples.
https://www.usingenglish.com/glossary.html - Contains definitions and examples of all those terms you vaguely remember from your elementary school days.
https://en.wiktionary.org/wiki/Wiktionary:Main_Page – A dictionary version of Wikipedia.
General:
https://en.wikipedia.org/wiki/Main_Page - It may not be that reliable, I suppose, but it's good for a quick fact.
https://www.nanowrimo.org/eng/forum - You can find anything here and the forum comes with its own resources thread that includes information on medicine, police stuff, geography, history and so many other things.
https://community.livejournal.com/little_details/ - A LJ community geared specifically towards helping writers do their research by answering their questions. It's already an impressive community filled with information (sorted by the tags) that you can't find practically anywhere else. PC writers with LJ accounts can also sign up for the community and ask away if they can't find the answer they need in the archives.
https://www.google.com - Best search engine in the world and your first stop before trying to tear your hair out over not finding things in Wikipedia first.
https://www.pgtc.com/~slmiller/fictiontips.htm - Contains articles on many sources of writing, including mechanics, characters, and other useful tips.