Cosmos is the datastore of implementations (in all programming languages) of all algorithms and datastructure one will encounter in a lifetime.
Cosmos on GitHub
You are free to contribute code in any language and explanations for a topic. Note that you are free to make any contribution you wish to make at OpenGenus. See this guide to understand how to use this task list. Following is a small collection of scopes you may contribute to:
Artificial Intelligence/ Machine Learning
 Add code for KMeans++ clustering algorithm
 Add code for Principal component analysis
 Add code for Agglomerative Hierarchical Clustering algorithm
 Add code for MeanShift Clustering algorithm
 Add code for Gaussian Expectation–Maximization Clustering algorithm
 Add code for ISODATA Clustering algorithm
 Add code for DBSCAN Clustering algorithm
 Add code for Fuzzy cmeans clustering algorithm
 Add code for Quality threshold clustering algorithm
 Add code for Kernel kmeans clustering algorithm
 Add code for MST based clustering algorithm
 Add code for Gradient boosting trees
 Add code for Gaussian mixture model
 Add code for Restricted boltzmann machine
 Add code for Support Vector Machines
 Add code for Random forests
DataStructures
 Add code for B+ tree
 Add code for Red Black tree
 Add code for R tree
 Add code for Two Three tree
 Add code for Circular Buffer
 Add code for Hash Table
 Add code for Hash Set
 Add code for Fenwick tree
Algorithms

Add code for various Dynamic Programming problems like:
 NewmanConway Sequence
 Different ways to sum n using numbers greater than or equal to m
 Number of decimal numbers of length k, that are strict monotone
 Ways to sum to N using array elements with repetition allowed
 Count number of ways to reach destination in a Maze
 Count all possible walks from a source to a destination with exactly k edges
 Count of Arithmetic Progression Subsequences in an array

Add code for various Greedy algorithms and problems like:
 Set cover problem
 Fractional Knapsack Problem
 Minimum operations to make GCD of array a multiple of k
 Maximize sum of consecutive differences in a circular array

Add code for various Numerical Analysis problems

Add code for various Operating System problems like:
 Optimal Page Replacement Algorithm
 Shortest Job First Scheduling
 Next Fit algorithm in Memory Management
 Best Fit algorithm in Memory Management
 First Fit algorithm in Memory Management

Add code for graph algorithms like:
 Topological sort
 Bron kerbosch algorithm
 Kahn’s Algorithm for Topological Sorting
 Bridges in a graph
 Johnson’s algorithm for Allpairs shortest paths
 Check whether a given graph is Bipartite
Online Challenges
 Add code for solutions of online challenges on various platforms like:
 Leetcode
 ProjectEuler
 HackerRank
 HackerEarth
 CodeForces
 CodeChef
 InterviewBit