Alongside client work and custom design, Pennyroyal developed a series of original capsule collections rooted in Tim's personal interests, obsessions, and travels. Each collection was built around a distinct concept — architecture, natural systems, mathematics, the cosmos — and executed in sterling silver with the same precision applied to every Pennyroyal project.

The collections released between 2009 and 2016 were:

-Alphabet, 2009
-Sculpture, 2011
-Empire, 2011
-Rampart, 2011
-Sierra, 2014
-Fibonacci, 2016
-Cosmos, 2016

The Pennyroyal capsule collections are no longer available. They remain an important part of the studio's creative history and a reflection of the independent design voice that has always run alongside the client work.

A collection of hand-pressed letters and symbols to mix and match with silver and bronze. The master models were made from pressed clay, then molded and cast in bronze and sterling silver.

This Alphabet Collection was retired in 2015.

A range of semi-wearable still-life sculptures inspired by European travels and impressionist style.

This collection is not currently available to purchase.

A collection of handmade interlocking ring structures handcrafted in wax and cast in solid sterling silver. Inspired by chain maille armor.

This collection is not currently available to purchase.

An exploration of art deco design themes, juxtaposed with organic, handcrafted textures.

The Empire Collection was retired in 2012.

The Sierra Collection was inspired by several extended camping, fishing, and hiking trips in the Sierra Nevada mountains.

The Sierra Collection was retired in 2015.

The Fibonacci collection was inspired by the seed pattern of a sunflower and the natural frequency and balance of the universe.

The Fibonacci Collection was retired in 2016.

The Cosmos Collection was inspired by the particulate nature of matter and the infinite mystery of the night sky.

The Cosmos Collection was retired in 2016.