How did I Accelerate Game Design, Development and Build

There are many aspects to consider when building a game. This requires a lot of knowledge, skills and time to build and integrate all the components.
Fortunately the Unity 3D platform has a great selection of packages and assets to accelerate the build of tools, models, shaders, sound effects, animations etc.

For the development of Math it Right 3D Adventure I've used the following Unity packages:

Addressables by Unity Technologies

The Addressable Asset System allows the developer to ask for an asset via its address. Once an asset (e.g. a prefab) is marked "addressable", it generates an address which can be called from anywhere. Wherever the asset resides (local or remote), the system will locate it and its dependencies, then return it.

Cinemachine by Unity Technologies

Smart camera tools for passionate creators. 

Input System by Unity Technologies

A new input system which can be used as a more extensible and customizable alternative to Unity's classic input system in UnityEngine.Input.

Post Processing by Unity Technologies

The post-processing stack (v2) comes with a collection of effects and image filters you can apply to your cameras to improve the visuals of your games.

Terrain Tools

The Terrain Tools package adds additonal terrain sculpting brushes and tools to your project to help create stunning terrain assets and ease the workflows.

TextMeshPro

TextMeshPro is the ultimate text solution for Unity. It's the perfect replacement for Unity's UI Text and the legacy Text Mesh.

Timeline

Use Unity Timeline to create cinematic content, game-play sequences, audio sequences, and complex particle effects.

Universal RP

The Universal Render Pipeline (URP) is a prebuilt Scriptable Render Pipeline, made by Unity. URP provides artist-friendly workflows that let you quickly and easily create optimized graphics across a range of platforms, from mobile to high-end consoles and PCs.

I've also used the following Unity Store Assets:

Confetti FX 2 by Archanor VFX

The asset also includes a new confetti-rain type emitter, as well as extra confetti textures, normal maps, documentation and more. Standard and URP support.

Dreamteck Splines by Dreamteck

Dreamteck Splines is designed to feel  like a native part of Unity, leveraging familiar tools and interfaces. It is both designer and programmer-friendly allowing for quick prototyping and implementing of unique behaviors. Focused on flexibility, ease of use and performance, it is suitable for both small, medium and large-scale projects.

Epic Toon FX by Archanor

Epic Toon FX is a huge collection of 930 cartoony particle effects. Standard and URP support.

Feel by More Mountains

Feel is the best way to improve your game's feel and make it extra juicy. Packed with more than 100 feedbacks, it'll let you easily trigger screenshakes, animate transforms, play with sounds, cameras, particles, physics, post processing, text, shaders, time, UI, and so much more.

Flat Kit: Toon Shading and Water by Dustyroom

The custom shading model is versatile enough to work great for classic cel/toon shading and for unique styles of experimental projects.

Highlight Plus by Kronnect

Highlight Plus is a powerful asset that adds outline, glow, overlay, see-through and other effects to any 3D object in your scene. HP has been designed with platform compatibility and performance in mind, as well as versatility.

HUD Navigation System by Sickscore Games

HUD Navigation System (HNS) is the ultimate collection of the most common navigation concepts from various games. It has been continuously developed, improved and tested since 2017. HNS is modular so you can easily disable features you don't need (unused features don't affect the performance).

Kinematic Character Controller by Philippe St-Armand

Character Controller a relatively low-level character controller solution that is not tied to any specific game genre and is made to be cleanly integrated into any project/architecture with as little friction or bloat as possible. Instead of using rigidbody physics, it uses a "collide and slide" algorithm that makes its movements perfectly fluid, precise and responsive. Note that its "kinematic" nature means that it will not get pushed by forces or rigidbodies automatically. These sorts of interactihttps://assetstore.unity.com/packages/tools/gui/text-animator-for-unity… have to be explicitly scripted.

Low Poly Animated Animals by Polyperfect

High quality rigged low poly animals with amazing animations, stunning demo scenes, multiple textures, sounds and Wander Script.

Odin - Inspector and Serializer by Sirenix

Odin puts your Unity workflow on steroids, making it easy to build powerful and advanced user-friendly editors for you and your entire team. 

Text Animator for Unity by Febucci Creations

Bring your dialogues to life, animating your game texts with this easy to use and customize plugin.