Random Options
Note
This will only explain the client side, please visit the original topic for more information about the server-side of it, if it's explained.
Disclaimer
I don't take any credit for the copied guide.
Introduction
In this guide I will introduce you how to implement custom Random Options.
I will use as an example the bonus "bAddEff".

Guide
To display our custom options must be added to data\luafiles514\lua files\datainfo\enumvar.lub and data\luafiles514\lua files\datainfo\addrandomoptionnametable.lub
enumvar.lub
Find:
And add:Info
The first number must be same that added in db\re\item_randomopt_db.yml
After completing all of the above your Random Option is ready to use.
Remember that there is documentation of how to add random options to items and a sample npc.