KDE Connect (FREE, open source) is definitely a gem. I love using my phone as a remote mouse and keyboard for my HTPC, and syncing clipboard, files, links, and notifications with the other devices I've paired with. (BTW, despite the name, you don't need KDE - or Linux even - to use it. It works on Windows and Android too.)

URLCheck (FREE, open source) is fantastic. It's a little pop-up that appears when you click a link, showing you the full URL and letting you modify it before you open with your browser/associated app (e.g., to remove tracking parameters):

URLCheck acts as an amazingly customizable and powerful intermediary when opening url links, allowing, among other things: to remove trackers, affiliate links, unnecessary elements, check Hosts, facilitating link holding and sharing, protecting against certain phishing techniques and many more...