Kihoon

Flexible Array is a Blender add-on by Kihoon for creating a curve array and adjusting the x and z axis volume with a brush. Density along the y axis is set for each point of the curve.

Base Mesh Tools - S is a Blender add-on for creating base meshes for sculpting. It lets you quickly create base meshes and transform them into various body shapes.

Complementary Weight / Advanced Gradient is a Blender add-on for weight painting. Complementary Weight links two connected bones so editing one adjusts the other, while Advanced Gradient controls the shape, offset, and intensity of weight gradients.