1. Chemistry and Crystallography

• Periodic table
• Inorganic crystal structure database (ICSD). Link 1 (require subscription), Link 2
• Other databases: NIMS - AtomWork, Mineral database, Cod
• Chose k-path
• Simplest thermodynamic phase diagrams: OQMD
• International crystallographic tables.

2. Physics

• Slater-coster parameters
• Fermi surfaces of simple metals
• Table of Shannon's ionic radii
• List of the 1st ionization potentials
  
• List of the Metal-metal bonds

3. Symmetry (mostly Bilbao Crystallographic Server)

• Convert CIF/POSCAR
• Space group list
• Wyckoff positions for all space groups
• Find symmetry tool

4. Searching Papers and books

5. Computer science

• LaTeX reference card
• Bash commands
• Free on-line pdf compressor.
• Notes on the use of the subversion
  

• Matrix operations on-line: Brunner's tools, BlueBit (column corresponds to each eigenvalue)
  

• Cecam workshops, Psi-k network conferences, List of the magnetic conferences

• Cheap tickets search: yandex, skyscanner.ru, hipmunk.com, kayak.com, anydayanyway.com
• Map of cheap flights: map.aviasales.ru
• Map of current flights: flightradar24.com
• Flight statistics (delay etc.): flightstats.com
• Prices in different countries: numbero.com
• Power sockets and plugs in different countries: world-power-plugs.com
• Time Zone Converter timeanddate.com
• Check english pronunciation forvo.com