Your challenge is simple: write as long of a pristine program as possible in the language of your choice using only unique bytes. (The full definition of a pristine program, copied from that link, is at the bottom of this question.)
That's right, no strings attached. Your code doesn't have to do anything at all, just run without erroring, meet the requirements for a pristine program (linked above), and include no duplicate bytes in the encoding you use.
For the purposes of the above explanation and linked definition of "pristine program", an error is defined as anything that causes the program to either entirely fail to run or to terminate with a nonzero exit code after a finite amount of time.
As this is code-bowling, longest, not shortest, code wins (measured by byte count). The maximum theoretically possible score is 256, as there are 256 distinct bytes possible. In case of a tie, the first answer at the highest score wins.
Here's the full definition of a pristine program, copied from the above link:
Let's define a pristine program as a program that does not have any errors itself but will error if you modify it by removing any contiguous substring of N characters, where
1 <= N < program length.
For example, the three character Python 2 program
is a pristine program because all the programs resulting from removing substrings of length 1 cause errors (syntax errors in fact, but any type of error will do):
8` `` `8
and also all the programs resulting from removing substrings of length 2 cause errors:
If, for example,
`8had been a non-erroring program then
`8`would not be pristine because all the results of substring removal must error.