Hey Nexus, MissCoriel here...
I don't see much activity in here when it comes to modders, however I believe we should try to help you in any medium as we can. This thread will show you what we use for modding!
First off, for the most useful information with music, sound effects, portraits, item codes, ect. Look no further than Cane's Modders Resource. It is packed with tons of information that is crucial for events, dialogue and beyond!
For more help with general modding, The Stardew Valley Wiki: Modding section has commands with descriptions and even information with near every aspect of modding with SMAPI and general game modding using Content Patcher, which i recommend you read it's documentation as well.
If you want to make NPCs, well I have your solution. My NPC Template will help push you into the right direction!
Need more than a few things to read? Need to talk to the pros? Why don't you chat with us directly!! The official discord for Stardew Valley Modding channel is filled with top rate modders who made the mods that you have installed even right now.
We are ready to help you achieve your dream!!