- AtCoder NoviSteps — AtCoder problem progression and progress tracker with 17 difficulty levels, problem sets, and per-problem status tracking.
- clist-ex — Contest dashboard based on clist.by, with LeetCode and CodeChef contest/problem tracking.
- CFTracker — Codeforces contest and problem tracker with ratings, tags, solve status, statistics, and practice lists.
- uHunt — UVa Online Judge progress tracker with solved problems, statistics, rankings, and virtual contests.
- uDebug - Community debugging platform with custom test cases, accepted outputs, hints, and discussions for online judge problems
- Kenkoooo - Collection of competitive programming tools, including the AtCoder Problems portal, virtual contests, and rating statistics
- Big-O Cheatsheet - Time complexity reference
- CP-Algorithms - Detailed algorithms and data structures
- clist.by - Aggregates upcoming contests from all judges
- monkeytype.com - Typing practice for faster coding
- eolymp.com - Collection of problems from CP olympiads
- Awesome CP Projects - Curated CP tools and resources
- Polygon - Platform for creating contest problems
- Graph Editor - Visualize and edit graphs online
- Virtual Judge - Host virtual contests using multiple OJs
- VisuAlgo - Algorithm and data structure visualizations
- OEIS - Database of integer sequences
- NIST DADS - Dictionary of algorithms and data structures
- Solved.ac - Rating and statistics for BOJ problems
- CPHOF - Codeforces performance hall of fame (stats)
- IOI Statistics - IOI medal and problem statistics
- USACO Guide - Free USACO training resources
- List of Algorithms
- CS 521 - Advanced Algorithm Design
- Codeforces Cheator Database
- Entrant Hub
- Codeforces Catalog
- Codeforces Anytime
- Codeforces Vizualizer (CFVIZ)
- Prac Hub
- Virtual Judge - Host virtual contests using multiple OJs
- The Ultimate Topic List - Comprehensive list of CP topics with problem references
- Getting into Competitive Programming - Comprehensive CP resource repo
- Competitive Programming Beginner Topics - Beginner topic collection
- Algorithms Princeton Lectures - Lecture slides and materials from Princeton
- A Second Course Notes - Notes for Stanford CS261
- Hacking a Google Interview (MIT) - Interview preparation materials