The UCLA Mesh Creator package allows you to easily create meshes from transparent images.

Generate mesh colliders, box colliders, or a bounding box with the mesh, as well as the ability to assign a physic material and texture material.

The UCLA Mesh Creator is great for creating 2D platformer games, quasi-3D games using an extruded look, or distant objects requiring physics in 3D games.

The UCLA Mesh Creator Wizard can be opened by navigating to: GameObject > Create Mesh Object