The Onion Omega 2 is a direct competitor to the Raspberry Pi Zero. Both have the same price point. Comparatively, the Pi Zero edges the Omega 2 in computing power and the HDMI output feature. But it is important to note the Omega 2 has built-in Wi-Fi and can be accessed from any web browser, eliminating the need for a dedicated HDMI port. For $4 extra, you can get the Omega 2 plus which has double the memory and storage.
Both of these devices are aimed at enthusiasts and provide ease of use with their modular designs and plug and play capabilities. They are both powered by Linux.
You can find more information on Omega 2’s kickstarter page.