Here’s a few resources that I’ve found especially useful over the years. They’re free unless stated otherwise.
I started using this towards the end of 2015, and it’s saved me a huge amount of time and effort while I’m writing my Masters assignments at uni. It has loads of really good features, allowing you to load your journal articles and make notes and comments directly onto them, which means you can cross reference really easily.
My favourite part, however, is the bibliography and citation plugin for Microsoft Word. This builds in-text citations and bibliographies in loads of different styles- Harvard, MHRA etc.
I’ve used MuseScore for a while, but really got into it when they updated to MuseScore 2. It’s very like Sibelius, allowing you to compile scores, which is really handy when you need to add a bit of score to an essay.
Trevor Herbert’s ‘Music In Words’
This book is not free, but there will probably be a copy in your library, especially if you’re at uni. It’s a really good book with loads of tips on researching and writing essays. Definitely worth a look!
Music Theory websites
I’ve used this a time or two myself, and always recommend it to music theory newcomers. It has good, clear explanations and exercises. What makes it really stand out for me is the ‘tools’ section. There are loads of useful tools such as interval and chord calculators- really helpful if you want to check your work!
I’ve only recently come across this, and I think it’s great! While it only goes up to grade 5, what it does include is really well presented and is really thorough.
This site not only covers all eight theory grades, but also has some handy quizzes. Not all of it free, but it does have several free courses.
This has a fairly comprehensive series of tutorials and a good set of ear training exercises.
I use this for all sorts of things. Although it is mainly supposed to be a practice aid, slowing down an audio file without changing pitch, I think it’s really useful for analyzing music and practicing my listening skills as well.
IMSLP basically got me through a good portion of my university courses. It’s a music wiki and has a huge range of public domain musical scores and recordings, among other things.