Gene enrichment tools

1. bioDBnet : 
It allows for conversions of identifiers from one database to other database identifiers or annotations.

2. DAVID
It provides a comprehensive set of functional annotation tools to understand biological meaning behind large list of genes.

3. WebGestalt
Translate large list of genes into biological insights, like the pathways, diseased network and gene ontology.
It categorizes the genes into three main categories such as Biological process, Cellular localization and Molecular function, these three are collectively called Gene Ontology.