Hydrangea Icosahedron
For folding Hydrangea Icosahedron (and many other shapes as well), you can just follow the instructions for Hydrangeaa Cube, ...
Modular spiky balls
Models of this type are also automatically listed in: abstract modular, abstract, geometric, mathematical object, modular, multi-sheet, spiky balls
Modular spiky balls (sometimes also called 3D stars) are among the most popular shapes folded from multiple units.
This page lists folding instructions for models of a single type. You might be interested in the models themselves instead.
Cosmos Ball
Instructions for the model were published in Meenakshi Mukerji’s book, Marvelous Modular Origami, on page 18.