Wordsmithing tools
www.oed.com/, dictionary.cambridge.org/dicti…, www.oxforddictionaries.com/ - ye olde faithful English dictionary.
www.oed.com/thesaurus/ - synonyms and historical development of words. Useful if you want to use words from a certain era.
www.thesaurus.com/ , en.oxforddictionaries.com/thes… - synonyms for everything.
www.powerthesaurus.org/ - like the above, but this site gives much broader answers. Handy if you are looking for a word, but only know a weak synonym for it.
ozdic.com/collocation-dictiona… - especially handy for non-native English speakers: this site tells you what word combinations make sense (damn you, prepositions!).
prowritingaid.com/ - a digital copy editor, checking your grammar, punctuation, sentence lengths, use of cliches, and lots of other stuff. Keep in mind, it's still a computer, but it points out a lot of useful things.
app.grammarly.com/ - this is an app that checks your grammar. It picks up errors prowritingaid does not, so I use them both.
chir.ag/projects/tip-of-my-ton… - you know that one word that's - wait for it - on the tip of your tongue? This site helps you figuring it out!
Map making and world building
worldbuildingschool.com/ - has some nice tutorials about a lot of things, especially about map making.
Fantasy Map TutorialxResources - some more map making.
donjon.bin.sh/ - to generate everything fantasy, from names to believable city sizes.
mythcreants.com/ - Lots of blog posts concerning lots of aspects of worldbuilding.
www.vulgarlang.com/index.html - for making your own conlang.
www.oldmapsonline.org/ - if you want to draw a map, and want some inspiration from old earth maps. Really pretty stuff here!
pamhage.wixsite.com/asoe/blog/… - my own blog, mainly about how to use various landscapes in your writing.
Writing tips
nanowrimo.org/forums/ - even if you don't like/have never done NaNoWriMo, their forum is a good place to go. The number of things that get covered that has something to do with writing is just mind blowing.
campnanowrimo.org/writing-reso… - more from the NaNoWriMo world...
fantasy-faction.com/ - everything about fantasy books; reviews, news, but also useful articles for writers.
writerswrite.co.za/25-proven-w… - how to get rid of a writer's block.
www.springhole.net/index.html - this one fits under all categories: helpful articles, random name generators, tips and tricks; too much to mention here!
www.youtube.com/channel/UCS_fc… - youtube channel of Jenna Moreci, who gives advice about pretty much everything.
writingexuses.com/ - podcast that also covers pretty much everything.
davidfarland.com/category/for-… - D. Farland's blog is made for writers and gives a lot of tips.
caharland.com/category/blog-gu… - Another blog you must follow, this one is by CA Harland. Rhymes nicely with the previous guy
[link] - the first of 5 videos explaining story structure by Dan Wells.
fantasynamegenerators.com/ - unlike the name implies, various writing tips can be found here too.
www.obsidianbookshelf.com/html… - how to describe certain aspects of your character, like eyes and hair.
mythcreants.com/ - blogs that cover pretty much everything.
www.youtube.com/playlist?list=… - Brandon Sanderson's course on (fantasy/sci-fi) writing. I love it, it covers pretty much everything and Brandon is a joy to listen to.
thewritelife.com/ - another site that covers everything writing-related.
www.livewritethrive.com/ - and another site that covers everything writing-related.
www.helpingwritersbecomeauthor…- and another another site that covers everything writing-related.
writerunboxed.com/ - and another3 site that covers everything writing-related.
Inspiration for characters and plots
tvtropes.org/ - enter at own risk. The place lists tropes used in tv-shows, films, books, comics, you name it. It will tell you how terribly unoriginal your ideas are, but it also sparks inspiration.
www.beleven.org/sagen/ - sorry, for Dutchies only. This site shows a list of Dutch legends. There are so many of them, but no one seems to know them any more. I use them as inspiration for the fairytales in my world.
nds-nl.wikipedia.org/wiki/Nede… - Okay, most of you will find this not useful at all. Even Dutchies might have trouble with it. This is a list of Low Saxon names (and their Dutch equivalent), but it's all in Low Saxon! It's the local dialect of the region I grew up in and I really like the names that go with it (I don't speak it myself though). I use some of them for my characters. Maybe you can use such a list to come up with names for your fantasy world too (edit: this is a nice place to start: www.behindthename.com).
fantasynamegenerators.com/ - not just generators for names, but generators for everything!