English test preparation
- IELTS official practice tests (IDP / British Council)Free official sample questions for all four sections
- Cambridge IELTS 12–19 practice booksReal past papers — the single most useful resource
- TOEFL official prep (ETS)Free sample sets and paid official practice tests
- British Council LearnEnglishFree grammar, listening and writing practice
- Duolingo English Test practiceFree practice test and score preview
GRE and GMAT
- ETS PowerPrep official practice testsTwo free official adaptive tests — use them as mocks, not practice
- Official GRE Guide (ETS)The official question book
- Manhattan Prep 5 lb. Book of GRE Practice ProblemsVolume practice by topic
- GregMat / Magoosh vocabulary decksWidely used for vocabulary and quant strategy
- GMAT Official Starter Kit (mba.com)Free official questions and two practice exams
Research skills and subject knowledge
- Google ScholarFind papers, professors and citation counts
- Connected PapersMap the literature around one paper visually
- arXivPreprints in physics, maths, CS, statistics and more
- Coursera — Academic English and research writingFree to audit; useful for SOP and proposal writing
- MIT OpenCourseWareFill gaps in undergraduate subjects before a Masters
- Overleaf LaTeX tutorialsWrite your CV, proposal and papers in LaTeX
- ZoteroFree reference manager — start using it before your proposal
Finding positions and scholarships
- EURAXESSOfficial EU portal for research positions across Europe
- jobs.ac.ukUK academic jobs and PhD studentships
- FindAPhDPhD projects, mostly UK and Europe
- DAAD scholarship databaseGermany: courses and funding
- Scholarships for DevelopmentScholarships aimed at developing-country students
- Chakrie: PhD and Masters openingsCollected here and refreshed weekly