List of NT prefixes - sourced from https://community.osr.com/discussion/72000/meaning-of-the-function-prefices

ntprefixes.txt

Cc = Cache manager (???)
Csr = Client Server support functions(LPC; related: CSRSS.EXE)
Dbg = Debugger support functions
Etw = Extended tracing ... support functions (???)
Ex = Executive
Fs = File system support functions
Hal = Hardware abstraction layer functions
Inbv = Something like: _In_itial _B_oot _V_ideo functions (???)
Io = I/O manager support functions
Kd = Kernel debugger support functions
Ki = Kernel interrupt support functions (???)
Ldr = PE image loader support functions
Lpc = LPC support functions
Lsa = Local security authority support functions
Mm = Memory manager support functions
Nls = Native language support functions
Ob = Object manager functions
Pfx = Name prefix support functions (???)
Po = Power management support functions
Ps = Process management support functions
Rtl = Runtime library functions
Rtlp = Private runtime library functions
Se = Security support functions
Wmi = Windows management instrumentation support functions
Vf = Verification (?) functions