UC Berkeley Data 8 (Foundations of Data Science)
Introductory data science/analytics course using Python; includes lectures, labs, and exercises for free online.
Stack Overflow - R Tag
A huge developer community answering detailed questions about R, packages, and applied statistics.
Build a Large Language Model from Scratch
Charanpal Dhanjal
A hands-on guide to constructing your own LLM using modern machine learning techniques
Power BI Community
Official Power BI community forum where users can ask questions, share solutions, and browse a large knowledge base of solved problems.
FlowingData
Visualization-focused tutorials and guides on analyzing and presenting data effectively.
Kaplan GRE Free Resources
Free practice tests, sample questions, and study materials from Kaplan.
IBM Data Analyst Professional Certificate (Audit Free)
Covers data analysis with Excel, SQL, Python, and data visualization tools, including projects and case studies; free in audit mode.
MiT Open CourseWare
MIT OpenCourseWare offers free access to thousands of MIT course materials?lectures, assignments, and exams?covering subjects from engineering and computer science to economics and the humanities. It's open learning at its best, with no registration required.
Art of Problem Solving (AoPS) Online Resources
Challenging problems, explanations, and articles designed for advanced high school and college-level students interested in problem solving and Olympiad-style math.
UK Fight Club (Professional Wargaming Network)
Community that promotes professional military wargaming and simulation activities across UK defense.
W3Schools Python
Step-by-step interactive lessons for Python basics, data structures, and functions, with hands-on coding snippets.
Khan Academy - Intro to SQL
Beginner-friendly course teaching SQL fundamentals with practice problems and video explanations.
R for Data Science (Hadley Wickham & Garrett Grolemund)
A free online book teaching R through the tidyverse approach, covering data wrangling, visualization, and modeling.
Kaggle Learn R
Hands-on mini-courses for R programming, data visualization, and machine learning with interactive notebooks in the browser.
OpenLearn - Learn to Code for Data Analysis
Free Open University course introducing Python programming in the context of data analysis.
Designing Machine Learning Systems
Chip Huyen
A practical blueprint for building production-ready ML systems with scalability and reliability
ETS GRE Official Prep
Free official materials from ETS including practice questions, POWERPREP online practice tests, and test-taker tips.