Type 2 and CFF fonts are the ne plus ultra of Adobe font technology. There has never been a Type 2 font or a CFF font.[C-25] If the reader finds these two sentences contradictory, she does not know Adobe very well. Let us clarify the matter (as much as we can): "Type 2"  is not a type of font but a type of charstring—in other words, a type of glyph description. The charstrings of traditional Type 1 fonts were of Type 1, without being aware of it. Now we have charstrings of Type 2, which are more powerful and more efficient.
[C-25] With the possible exception of a few fonts woven on the spot into the PDF files produced by Acrobat Distiller. We have learned that FontForge will henceforth produce CFF fonts without an OpenType wrapper.
CFF (for "compact font format")  is not a font format either, despite its name. It is a way to compress existing font formats, in particular the two most successful formats: Type 1 fonts and CIDs.
Wait! We are not finished. When we compress Type 1 or CID fonts, Adobe requires us to use charstrings of Type 2. Can we use the result as an alternative to traditional fonts? Is it a new type of font? Not at all! The only way to use a CFF font is within an OpenType font, in the form of a CFF table.
Thus both Type 2 and the CFF format were created to make PostScript fonts easier to incorporate into an OpenType font structure.[C-26] There has been a precursor to this: at some time, in the early days, it was possible to insert a complete ...