DFT Software I have been using ultimately

Quantum ESPRESSO
Some notes on Quantum ESPRESSO

Elk

GW and Bethe-Salpeter Software

Yambo
BerkeleyGW

Various (other) DFT Software

ABINIT
WIEN2k
SIESTA
AIMPRO
AIMPRO
OCTOPUS
OPIUM
GAMESS
FHI98PP

Pseudopotentials

Theos Server
Cornell
APE
Crystal
Pseudo-potential library (Andrea dal Corso)
Pseudo-Dojo
Standard Solid State Pseudopotentials

Band unfolding

BandUP

Atom manipulation and visualization

Atomsk
XCrysDen