Diamond/shard shape with a little bit of particle system flavour. Instanced drawing of the particles is good but I'm not sure if it's faster to send the transform per instance or do the vertex transform work on the GPU. Either way, this one is done on the GPU because I hadn't done it that way before.

Random vertices on a disk and a sphere, joined to their closest relative, then interpolated between the two states, rotated.

Simple regular polygons, arranged and animated in a (hopefully) pleasing way. Colour palette is "Paradise Wedding."