My code in order till the line.

drives = [ chr(x) + ":\\" for x in range(65,91) if os.path.exists(chr(x) + ":\\") ]

I see all the extentions of files in a specified disk with this code block

ListFiles = os.walk("d:\\") #normally putting drives here. and getting an error.
SplitTypes = []
for walk_output in ListFiles:
    for file_name in walk_output[-1]:
        SplitTypes.append(file_name.split(".")[-1])

print(SplitTypes)

with this

counter = 0
inp = SplitTypes
for drive in drives:
    for r, d, f in os.walk(drive):
        for file in f:
            filepath = os.path.join(r, file)
            if inp in file:
                counter += 1
                print(os.path.join(r, file))           
print(f"counted {counter} files.")

Second code block prints out all the file’s extentions such as: txt, png, exe, dll etc. \
Example:

['epr',itx', 'itx', 'ilut', 'itx', 'itx', 'cube', 'cube', 'cube', 'itx', 'cube', 'cube''js','dll', 'dll', 'dll', 'json', 'json', 'json', 'json', 'json', 'json', 'json', 'json', 'json', 'json''rar', 'rar', 'ini', 'chm', 'dll', 'dll', 'dll', 'exe', 'sfx', 'sfx', 'exe', 'exe', 'ion', 'txt', 'txt', 'txt', 'exe', 'txt', 'txt', 'txt', 'txt', 
'txt', 'txt', 'txt',]

The problem I’m facing here is I can’t scan for extensions in all drivers (second block of code).
And I can’t search all the files with the extensions that (second block of code) provided to third block of code.
For better Understanding you can think like this is an antivirus doing a complete scan on your PC.