SnapEdit

This is the kind of tool that just works and then gets out of your way. The clipboard-to-clipboard workflow is genuinely smart — no desktop clutter, no "save as" dialogs interrupting your flow, just Ctrl+shift+V to grab an image, make your edit, and Cmd+C to slap it straight into Slack or whatever. The keyboard shortcut mapping is intuitive since it mirrors how we naturally paste things, and being completely free is a smart play for traction among power users who deal with screenshots daily. Not revolutionary, but that's the point — it's a low-key utility that's going to ship under the radar and then everyone wonders how they lived without it.