The vast networks of connected devices in the Internet of Things (IoT) ecosystem can enable energy-efficient buildings, contributing to the reduction of greenhouse gas emissions. While IoT devices are traditionally powered by batteries, indoor photovoltaics (IPVs) offer a sustainable solution by harnessing widely available ambient indoor light energy. Vibrant research is devoted to identifying low-cost, efficient, and stable indoor light harvesters. Metal halide perovskites and their derivatives play a key role in this research. This chapter discusses the current status and challenges of low-toxicity lead-free perovskites and their derivatives in IPVs and suggests ways to improve their performance.