Power Primitives Add-On is a Blender add-on for low poly modeling and blocking, adding 30 new primitive shapes to work with. The set includes cubes, pyramids, spheres, cones with 5 or 6 sides, a frustum cone, prisms, cylinders, a star-shaped prism, grids, discs, octahedra, bipyramids, a quartz crystal, tetrahedra, triangular prisms, icosahedra, dodecahedra, several torus sections, hollow boxes, hollow cylinders, quad spheres, and geospheres of 32 and 80 faces.
Each shape can be added to the scene or used to replace the current selection, which lets you try different shapes when you are unsure. You can keep your current selection instead of replacing it, so new shapes can be positioned later. A Transform-when-added setting activates the Transform gizmo the moment a Power Primitive is added, and you can choose the scale applied to new shapes, set by default to a size similar to Blender's default cube.
The add-on ships with a PDF tutorial covering installation and use, plus a video tutorial that is included with the product and available on the developer's YouTube channel.