passwordstore.org is good if you're a nerd. It's built on standard linux tools: pwgen, gnupg, git. QTPass is a QT based multi-platform desktop gui version. That helps if you're not in the mood to be a nerd today. Android Password Store is the mobile version and integrates with Android chrome/chromium. Thanks to gnupg, pass also works in conjunction with smartcards like Yubikeys. Open Keychain on android allows you to use a Yubikey Neo with Android Password Store. PassFF is the Firefox plugin.
Usage: It's a git repo with passwords stored in encrypted text files. Syncing is done by push/pull the git repo. Since it is git, you have a record of every password you ever generated. Unlocking a password with a Yubikey requires a pin entry and a physical touch. Once entered, the key is available for further passwords without pin, but a Yubikey 4 can be configured to require a touch every time if you're worried about compromised hardware stealing your entire password database.
There's no import from other managers that I'm aware of, but it might exist. Googling stuff about 'pass' is tedious. Google for 'zx2c4 pass' and you'll have better results.