Hey I might be a little biased as the developer, but my favorite tool is Fuzzy Brain! It's a Unity asset that gives you a different way to build game logic. It separates decision-making logic from behavior implementation, which keeps your code cleaner and more focused while making behaviors easier to create, modify, reuse, and maintain.
It's based on Valve's bark system, but expanded to be used for many different things, not just speech. I completely optimized it for unity and fully integrated it into the editor!
It's my favorite tool, because it promotes separation of concerns, keeping decision-making logic separated from behavior implementation. This helps keep code clean so your gameplay code doesn't become filled with decision-making and branching. It Reduces complex if/else logic making code easier to maintain and modify.
Fuzzy Brain shifts your control logic to data-driven design so behavior can be assembled from data rather than hard-coded control flow. this allows non programmers to author behaviours without needing the assistance of a programmer, which means less back and forth and faster iteration.
The system is really simple, There are 3 key parts, Conditions, Acts and Actors, Acts have a list of Conditions that are evaluated by the Actor to select the Act to run. The whole ting can be represented as a simple spreadsheet, no messy behaviour trees or complex state machines, no weights to balance. Can be used for simple or complex behaviours and great for making reactive or emergent gameplay.
For more information check out the webpage:
https://fuzzybrain.page.gd/
Fuzzy Brain is available on the unity asset store:
https://assetstore.unity.com/packages/tools/behavior-ai/fuzzy-brain-349538