Because I didn't see a post about all ELO-categories on this forum before, I will attempt to explain my analysis about the different ranks and make a prediction for Gold and Platinum Leagues.
First of all, let's look at the Bronze league. As most of us have passed through all ranks, we know what the ELO-boundaries for each rank/class are. But if we take a closer look, we can extract a pattern:
If we write down the difference between each class in the Delta-row, and repeat this process, we see that the Delta-Delta row is constant (which indicates polynomial growth of the 2nd order (quadratic)).
Now let us look at my calculations for the Silver League:
Here we observe the Delta-Delta value to be alternating between 14 and 16, probably because 15 would yield values that would be percieved as 'strange' boundaries by humans. Furthermore, we observe the first Delta-increase to be 8: roughly half the Delta-Delta value. We observed this pattern within the Bronze League too: the first Delta value of 5 was half the Delta-Delta constant.
Based on this analysis of the pattern, we can predict the ELO-classes for Gold and Platinum leagues as follows: (I wrote a very simple program that calculated these tables for me )
Furthermore, we observe the total span of the Bronze league to be 500, Silver to be 750, and according to my predictions Gold to be 1000 and Platinum to be 1250, which also fit another pattern. Therefore, I am pretty confident these values are correct.
I hope someone finds this blah-blah interesting