connected

CONNECTED is Rat King's stand-alone tool for all kinds of semi-scripted dialogues and is/was used in some of their projects (Behind Stars and Under Hills, Patou, Mops & Mobs).

The documentation (for using the editor) is here.

In order to use the .json files created with CONNECTED inside your game, you'll need to parse them and execute the resulting graph of nodes. This can be done in any way you prefer, but for Unity and Godot games, there are downloads below that provide the necessary code as a start or inspiration.

The lite edition of CONNECTED is free. The pro edition ($7.99) allows defining new node types and also manipulate the standard ones. It also lets you save the texts of all nodes in a separate JSON file, for easier localisation.