Clustering algorithms 

Clustering algos are the algos for unsupervised learning. 

Data is provided to them without labels and the algo clusters them into groups. 

There are 3 types of clustering algorithms : 

Desnsity Based : DBSCAN , OPTICS

Distribution Based : 

Centroid Based : K-means, Gaussian Mixture Model, BIRCH

BIRCH-> Balance Iterative Reducing and Clustering using Hierarchies

OPTICS->Ordering Points to Identify Clustering Structure