| [Wannier90](http://www.wannier.org) | A tool for obtaining maximally-localised Wannier functions |
| [WIEN2k](http://www.wien2k.at/) | The program package WIEN2k allows to perform electronic structure calculations of solids using density functional theory (DFT). It is based on the full-potential (linearized) augmented plane-wave ((L)APW) + local orbitals (lo) method, one among the most accurate schemes for band structure calculations. WIEN2k is an all-electron scheme including relativistic effects and has many features. |
| [XCFun](https://xcfun.readthedocs.io) | Arbitrary order exchange-correlation functional library |
| [xtb](https://xtb-docs.readthedocs.io) | xtb - An extended tight-binding semi-empirical program package. |