This topic came about a couple of months ago... meaning it's now 'dead', if you will... however, I think the topic should be refreshed here, as (imo) the prospects of it were rather interesting.
So what is your view on why some types have strength over/are weak towards specific types of Pokémon attacks? For example(s):
Fire-type attacks are 'super effective' against Grass-type Pokémon. Why?
Some forms of grass and (in general) vegetation are known to be combustible, thus making them easier to catch on fire (and potentially spread like a wildfire). In other words, you could say that grass/vegetation (in many cases) is prone to catching on fire if contact is made with it. Correlation is made because, as seen, grass/vegetation is vulnerable to fire, making Fire-type attacks, in Pokémon terms, 'super effective' against Grass-types.
Grass-type attacks are 'not very effective' against Fire-type Pokémon. Why?
With grass/vegetation being easily (again, in most cases) combustible with fire, the grass/vegetation is left in ash and debris due to consumption by the fire. Knowing that fire already has this kind of effect on grass/vegetation, correlation can be made - similar to the case above. Grass-type Pokémon's Grass-type attacks are 'not very effective' aimed at Fire-types because grass/vegetation coming in contact with fire causes it to combust and disintegrate.
There are tons of various ideas to speculate on with this (topic) subject. Have fun with it!