I will discuss ideas and prospects to search for sub-GeV dark matter, below the typical thresholds of current direct detection experiments. In this mass range, there are a variety of interesting and well-motivated models, and detecting them may require new kinds of low-threshold experiments. I will focus on a few specific examples. First, I show that current semiconductor and proposed superconductor targets are a powerful probe of light (meV-keV) bosonic dark matter, via an absorption signal. I will then discuss superfluid helium as a target material, and show that it could be used to probe nuclear recoils from keV-GeV dark matter.