To zoom pages by default in Firefox, open the about:config page via the location/address bar, and change the value of layout.css.devPixelsPerPx to fx 1.2, to zoom in 120% on all pages by default. This will also increase the size of icons and tabs, but this way you don't need an add-on for larger text on all web pages by default.
From Firefox 57 onwards, Add-ons will stop working and be replaced with WebExtensions. One very used Add-on is Self-Destructing Cookies, but this extension will not be rewritten as a WebExtension. As a replacement you can use Cookie AutoDelete.
The Keyword field in Firefox Bookmarks can be used to create shortcuts and smart searches. For some reason, sometimes if you define a new keyword, the latest keyword will be deleted. Keeping track of your keywords is hard though, since there isn't a way to list all keywords in use...