Yey!

Sculpt Layers is a Blender addon from Yey!, creator of MiraTools, that stores your base mesh and lets you build detail up as separate layers. It works with the Multires modifier and imports layers from ZBrush.

Bengine For Unity connects Blender's Geometry Nodes to Unity, letting you generate procedural meshes and levels inside the engine. It supports Sverchok nodes, Unity terrain, curves, and networking between Blender and Unity.

Black Mesh is a procedural voxel modeling add-on for Blender, bringing boolean voxels, smooth voxels, layers and a non-destructive workflow aimed at sci-fi work. It can also combine with other boolean tools.

BSpheres is a Blender addon inspired by the sphere tools in ZBrush and 3DCoat. It builds base shapes for characters, creatures and other forms for sculpting, prototyping and animation.

Decal On The Shell is a Blender addon for adding decals to models. It ships with 50+ decals, needs no textures or normal maps, and works on meshes using the SubD modifier.

Rune is a brush manager for sculpting in Blender, built by Yey!. It stores and saves sculpting brushes, runs from a separate window, and lets you add custom brushes bought on BlenderMarket or ArtStation.

BEngine For Unreal connects Blender's Geometry Nodes to Unreal Engine, letting you generate meshes and instances inside UE 5.1+ using Blender's procedural power. Data is sent between the two applications over networking.