Fill ComboBox with List of available Fonts

Not sure why we need to foreach here.

IList<string> fontNames = FontFamily.Families.Select(f => f.Name).ToList();

You can use System.Drawing.FontFamily.Families to get the available fonts.

List<string> fonts = new List<string>();

foreach (FontFamily font in System.Drawing.FontFamily.Families)
{
    fonts.Add(font.Name);
}

// add the fonts to your ComboBox here