Multi-Dialect Writers (British/Australian/Canadian)
Austin Peay State University provides an extremely helpful guide for academic writers on UK vs American English. https://www.apsu.edu/writingcenter/writing-resources/british-american-english.pdf
Eleven tackles a bunch of quirkier usage and vocabulary issues in the UK/US space. https://www.elevenwriting.com/blog/british-english-vs-american-english
Most common mistakes that proofreaders catch (US, UK, AUS)
https://proofed.co.uk/knowledge-hub/a-proofreaders-guide-to-british-american-and-australian-english
Multi-Lingual Writers
The incomparable Purdue Online Writing Lab has, as always, a fantastic resource for multilingual writers, including worksheets on specific issues, skills, and needs (i.e., adjective versus adverb use, nominalizations, paraphrasing, punctuation). https://owl.purdue.edu/owl/multilingual/multilingual_students/index.html
Wesleyan University has an incredible webpage for multilingual writers that stresses both using all your languages as resources when writing and understanding key differences between other languages and academic English. Their site includes resources for conventions of academic English, reading and research strategies for L2 writers, and much more.
https://www.wesleyan.edu/writing/Current%20Multilingual-writers/
ELSDesk has a fantastic Academic Word Bank that includes pronunciation and usage of nearly 600 words that occur frequently in academic writing.
https://esldesk.com/vocabulary/academic/