Sharing economy services have become increasingly popular. In addition to various well-known for-profit activities in this space (e.g., ride and apartment sharing), many community groups and non-profit organizations offer collections of shared things (e.g., books, tools) that explicitly aim to benefit local communities. We expect that both non-profit and for-profit approaches will see an increased use in the future. To support designers in devising new sharing economy services, we developed the Sharing Economy Design Cards, a design toolkit in the form of a card deck. We present two deployments of the cards: (1) in individual interviews with 16 designers and sharing economy domain experts; and (2) in two workshops with 5 participants each. Our findings show that the use of the cards not only facilitates the creation of future sharing platforms and services in a collaborative setting, but also helps to evaluate existing sharing economy services as an individual activity.