OK here is a list of console commands you can use when playing on your own server. Before trying most of these you will need to put sv_cheats 1 into the console.
For taking screenshots:
r_drawviewmodel 0 (this removes the player’s gun model)
cl_drawhud 0 (this removes the HUD)
noclip (allows you to fly around the map, through walls etc)
give weapon_ak47 (for an AK)
give weapon_m4a1 (for m4)
give weapon_awp (for awp)
give weapon_smokegrenade (for smoke)
give weapon_flashbang (for flash)
sv_showimpacts 1 (to highlight bullet impact locations)
More as I remember them!