Increase Drop Rate

You will need BepInEx installed, 
Extract the dll into BepInEx/plugins folder (the folder will automaticall create on first game run, or you can create it yourself)

The config file will only generated after first run at BepInEx\config\rrinda.lootmanager.cfg,

In this game, items have six quality tier from 1-6, the higher the rarer, normally the drop rate of higher tier are super low (2-5%) except for some fixed items drop,

with this mod you can customize the drop rate of any tier (including modded item set), the configs already set for a fair drop rate, so you can just use it, or custom it whatever you want to.

How it works:
in the config file generated, you will see [Quality Weights] section
tl:dr: the bigger weight > higher drop change

we only need to care about below lines
Quality1 = 30
Quality2 = 30
Quality3 = 30
Quality4 = 20
Quality5 = 20
Quality6 = 10

total weight of all quality = 140

basically their drop rate will be calculated based on their weight, 
for example quality 1 = 30 / (total weight: 140) ~ 21%
quality 6 = 10/140 ~7%