Of course, you have all seen a periodic table. Now, I present to you a periodic table that goes borderline information overload.
For each element, the element symbol is written in the center of the block. The background color represents the color of the element’s elemental form at standard state. In the upper right is the atomic number. Right below it is the number of neutrons in the most common isotope of the element. In the bottom right is the number of stable isotopes of the element. If this number is positive, the number above it gives the isotope percentage abundance of the most common isotope, rounded down, and otherwise, it is the natural log of the half-life of the most stable isotope in years, rounded down. At the bottom, the letter to the left represents the crystal structure of the element (Cubic, Hexagonal, Orthorhombic, Trigonal, Tetragonal [Q], Rhombohedral, Monoclinic), and the letter to the right represents the magnetic ordering of the element at standard state (Diamagnetic, Paramagnetic, Ferromagnetic, Antiferromagnetic). To the left of this, and going clockwise, are ranks among elements for which data is given for: specific heat capacity at standard state, boiling point at one bar, melting point at one bar, density at standard state, electrical conductivity at standard state, and thermal conductivity at standard state. The element ranked “n” has the nth highest value of the property out of the elements in the table for which the value is known, and the element ranked “[n]” has the nth lowest value.
(UPDATE: Or, if you didn’t want to digest all of that and wanted a graphical key, here’s one by betaveros.)