There are many programs on the market to help you keep your fonts organised. Depending on the number of fonts you have, different programs may be better for you than others. It also depends on what you want from a program.
The most basic way to keep your fonts organised is via your own PC. You can keep them all together in a separate folder on your C drive or on an external hard drive. you may want to keep your fonts organised via bundle or type. This unfortunately does not give you the ability to look at your fonts at a glance or compare font types side by side.
Below I will give you a short overview on 4 of the most popular font organizers on the market.