Physical props serving as proxies for virtual objects (haptic proxies) offer a cheap, convenient, and compelling way of delivering a sense of touch in virtual reality (VR). To successfully use haptic proxies for VR, they have to be both similar to and colocated with their virtual counterparts. In this article, we introduce a taxonomy organizing techniques using haptic proxies for VR into eight categories based on when the techniques are deployed (offline or real-time), what reality is being manipulated (physical or virtual reality), and the purpose of the techniques (to affect object perception or the mapping between real and virtual objects). Finally, we discuss key advantages and limitations of the different categories of techniques.