trackr.sh is described as 'Store your bookmarks in trackr.sh and never loose track of those great links. You can categorize your bookmarks using tags to quickly find the links you need. Store a copy of the bookmarked link so you never loose access to the content you need' and is an website in the Web Browsers category. There are more than 10 alternatives to trackr.sh, not only websites but also apps for a variety of platforms, including Firefox, Google Chrome, Self-Hosted solutions and Vivaldi Browser. The best alternative is Raindrop.io, which is both free and Open Source. Other great sites and apps similar to trackr.sh are Firefox Sync (Free, Open Source), start.me (Freemium), Tagpacker (Free) and historious (Freemium).
Sorted is an extension for Firefox. Use this if you find yourself manually creating bookmark folders. Just enter the words commonly occurring in your bookmark titles and this extension will automatically create folders and move your bookmarks.