Bleacher report, a free website that distributes articles written by and about Bleacher Nation, has a list of font choices for Shreks 2 script fonts.
You can see it here.
For Shrek, you can use the lettering from the first film or the letterboxing from the second film.
You can also use letterboxing to create new characters.
There are some letterboxing options for Shreveport, where you can create new Shrek characters.
Here is an example.
Here is another example, this time with letterboxing for a character from the third film.
This is another letterboxing example.
You can choose between different letterboxing fonts to create different Shrek voices.
In this example, I chose the letterboxing from Shrek 3.
Here are some more examples.
I have also included an example that has letterboxing added for the character of Prince Shrek from the fourth film.