Why cant I find a chart of materials where each point is a material, and the y axis is thermal conductivity and the x-axis is specific heat capacity

@freemo The style of chart you're looking for is an Ashby chart. With some google-foo, the closest flavor of Ashby chart to what you want I could find publicly available is this:

@freemo The relation between diffusivity (a) and specific heat (Cp) is:
a = k / (rho * Cp)
where k is conductivity, rho is density. So the X axis in this chart is inversely proportional to Cp, but also proportional to k (the y-axis!). The 45 degree dashed lines in the chart are isometric to volumetric specific heat.

@GregWilson

This actually answers what I suspected and wanted to answer. I was wondering if the chart would be nice and well ordered (and if so in what way) or just a random jumble with no real relationship... IT is interesting to see that like I suspected there is indeed a close correlation/pattern relating the two across materials.

I was also thinking how some material with really high specific heat capacity and high conductivity would be a very special thing to have, since you can store a lot of energy in it and get that energy out quickly, which in term of energy dynamics is a bit of a holy grail (like in electronics you tend to get one or the other and not both)