Mail Framework Mod is a utility for modders that allows you to create and edit the texts of letters and messages in the Stardew Valley game.

SMAPI - Stardew Modding API - is a utility for Stardew Valley that will allow you to install most of the game's mods. Follow the installer instructions.

The Content Patcher mod will add a utility that will allow you to add and dynamically change in-game events, maps, characters, and more. However, content packs for Content Patcher must be installed manually.

Framework required for many other mods to work. Installation path: Stardew Valley/Mods

Farm Type Manager (FTM) - a utility for Stardew Valley that allows you to edit and create any objects on the map. As an example, you can spawn monsters (or any other objects) with a certain chance in a specified location at a specified time. There are ready-made mods that are automatically integrated with FTM.

The next mod for experienced Stardew Valley players, Json Assets. The mod adds new items that interact with crafting in the game.

Flexible and easy to use in-game menu with plenty of cheats for Stardew Valley.

If you are a newcomer to the game Stardew Valley, then the Lookup Anything mod will be indispensable for you. It will show detailed information literally about everything. Hover your cursor over the object or character of interest to you, press F1 and detailed information about it will appear.