I have ADHD. So most of the time I don't even have time to write an interesting idea until a new pops up.
For example(short) I had this idea after reading Solo leveling type manwa where gate clearing and things happen.
What if after clearing a tower/gate rather than just disappearing they just flush out everything in them like at the speed of bullet everything inside becomes a paste.
So if you don't clear a gate soon you will have uncountable number of mobs to fight if you clear a gate/tower you will have to be prepared to be bombarded with everything that gate/tower had.
The only way to slow down is for a certain number of hunter to be present in the tower/gate, it doesn't matter the rank of their well being as long as they are "hunters" it will do. But even this had a side effect—monster in tower will become stronger and stronger the longer you slow it down. If hunters are present in the tower then the monster will be "forced" to act like game monsters having specific fight patterns and "area of presence".
There was more such as government secretly kidnapping weak hunters and make them live in hard to clear towers, organisation trying to evolve weak tower/gates to higher ranks.
There is also tower ranks— Common>Normal>Rare>Special>Mythic>Legend
Common are just your regular gates(in this setting) but their frequency is highest and they can be "harvested" before clearing.
Normal, gates after clearing don't leave anything and you also can't take anything out of them, their danger level upgrades super fast.
Rare gates can only be cleared after killing the boss every clearer gets a curse and blessing (always miss balanced in the favour of curse, especially "Heart or Righteous", a curse that makes the cursed believe everything they do is right.)
Special, a rank given to many types of gates)towers they can un-clrearable, Unhabitaed, have a fully functioning human habitable city(these will force people in them to work), a simple unbreakable building, a micro-verse etc.
Mythic, can only be cleared solo, clearing these tower let's the clearer make one wish, any wish literally without any catch. (That's how in this setting the hunter system came to existence)
Legend, places that became gates/tower after "The Gatefall"(term for the existence of thowers) such as seven wonders, renowned old places, historical sites. Only those with "special titles" related to them can enter. Basically seven deadly sins, different lords, different masters, coloured etc.
Did I cover everything I don't know?
The plot will be too big, if someone wants they can.