Klipper is great if you're using KDE and prefer something integrated with your desktop environment. It gives you a history, popup UI, and mouse-driven selection.

ClipCapsule is more minimal and focused on a keyboard-only workflow. The idea is that you can hit something like CTRL + SHIFT + 3 and instantly move that item to the top of your clipboard stack, so the next CTRL + V pastes it. No popups, no menus,just fast switching.

It’s also built in Go and Wails, and listens for raw keyboard events (currently X11-only), so it works outside of any particular desktop environment. Still early, but it’s aimed at people who prefer keeping their hands on the keyboard.