Search notes:

commands

Memory related

d* Displays the content of memory
m Move (copy) data
fp fill physical memory
c compare
s searches for data in memory
!db, !dc, !dd, !dp, !du, !dw read from physical address
!eb, !ed write to physical address
!search search in physical memory
!vtop, !pte convert a virtual address to a physical address.
.holdmem

Extensions

Commands that start with an exclamation mark (!) are extensions. These are exported from a DLL which users can create to extend the functionality of WinDbg.
Displaying information about the PEB and the TEB 
!peb
!teb
Compare the previous two commands with: 
dt nt!_PEB
dt nt!_PEB -r @$peb
dt nt!_TEB
Apparently, there are quite a few commands that rely on information found in the PEB and TEB: lm, !dlls, !imgreloc, !tls, !gle

Address related

!address addr and !vprot addr display memory related information (protection, type, usage…) 
!address rdx
!vprot   rdx

See also

The initial command can be specified with the -c command line option.
With the JavaScript scripting extension, it is possible to execute a command like so: 
if (…) {
   host.namespace.Debugger.Utility.Control.ExecuteCommand("g");
}

Index