I got one of the HiFive Rev B boards to experiment with because I'd really like for my hardware projects to be as open as possible, even down to the silicon level.
Here's a related review. https://hackspace.raspberrypi.org/features/sifive-hifive1-review
Makerdon is a Mastodon instance focused on Makers, Open Source Hardware (OSHW) and STEM/STEAM. Free and Open Source Software (FOSS) is a likely topic as well. If you're interested in making things, allowing others to build on your work, and/or teaching others about making things, you might like this instance.