OnlyKey looks interesting. A few things make me skeptical though: It only supports 24 accounts, which is two orders of magnitude fewer than I have in my password manager. And the hardware design doesn't look super convenient or durable. I bought a YubiKey a few years ago, and kept in on my keychain, and before I had even used it a dozen times, the entire thing disintegrated and became unusable.
Edit: I'm also a bit uneasy about securing access to all by accounts by one single PIN that can be used to unlock a physical device that is easy for someone to steal unnoticed.
