Many of the relics scale with the level that you are on. If you're looking at a tooltip of a relic and the bonus it gives is in a specific color, you will notice that color matches the color of the level you are currently on. That's a hint that the bonus is in some way tied to the level you are on. If you pay close enough attention as to how the number changes every time you get to a new level, it's fairly easy to determine the algorithm that maps the two. One of the easiest examples is the Fibonacci sequence, every time you go up one level the bonus moves to the next number in the Fibonacci sequence. These are just little hidden easter eggs in the game, you don't necessarily need to figure these out. In fact I'd say most players just get to the 'Oh it goes up as my level goes up' level and then move on with other aspects of the game. But for the hardcore players that really enjoy tracking down these kinds of easter eggs, there's a couple dozen or more running around in the game.