"Powerful letter font manager that lets you view and save the ones you like best in a favourites file."
Surely there are many letter fonts installed in your computer, but do you really know how many, or which ones you prefer? For this you need a tool that works as a font administrator, like Nexus Font.
As you can probably imagine, Nexus Font lets you view all the fonts so you can choose the ones you like best. You can compare many at the same time, install new ones, uninstall existing ones you don`t like, etc. Also, Nexus Font includes other functions like the possibility of searching and finding letter fonts that are duplicated, or deleting unnecessary font files. It has other editing tools like cut, copy, paste, etc.
You don't need to install all fonts to the system. You can load fonts you are working with only. And to always have those fonts you like best easy to find, with Nexus Font you can group them in a favourites list, or print them to see how they look on paper.