I saw someone in a video have a separate window in illustrator where they had a list of some fonts they used often, does anyone know how to do that?
I personally use the DiskFonts plugin. It isn't a free plugin ($29) but works well. It allows you to sort fonts, mark favorites, create font lists and categories and can all be done from a separate folder of fonts. Here is a brief description:
Font viewer, font browser and manager. Displays fonts from hard disk inside Adobe Suite: Photoshop, Illustrator, InDesign, Flash, Dreamweaver, Premiere, Fireworks support Supports TrueType fonts, OpenType fonts, PostScript fonts and many other formats.
You don't have to load all of the fonts into Adobe to use and view them. It also lets you use a mobile device as an external fonts panel, which is pretty cool.
In Adobe Creative Cloud there's Libraries which is quite possibly what you saw. Impossible to know for sure without a screenshot.
Window > Libraries the nice part is if you work across multiple applications within the Adobe Suite it syncs up. So for me I generally design first in Photoshop but then create the final Print Ready in InDesign. It saves me a little time if I drop the styles and colors into the Library instead of having to refer back and forth to get the exact CMYK values for them. Can also be used to store main branding colors and styles that appear on all marketing collateral.