p4vasp is a visualization suite for the Vienna Ab-initio Simulation Package (VASP). It contains an extensible Graphical User Interface framework, that can be used to view material structures, density of states, band-structures and more. It provides a Python library that simplifies the process of manipulation of the VASP input and output data, via the use of Python scripts.
More information about this tool can be found under Ref. 1.