If they're lucky and fast
PCs Defeating the Creature May Get All 3 Lists
The creature entry Combat Gear was first used in Complete Psionic for Pathfinder's antecedent Dungeons and Dragons 3.5, but it wasn't until 4 months later that the Monster Manual IV explained on page 5 of that the entry includes
Possessions that the creature can choose to employ on its turn as an action appear here. Such items might include doses of poison (applied poisons, not natural ones), scrolls, potions, oils, wands, staffs, rods, and other wondrous items.
This is--despite the definition--different from the creature entry Possessions, also explained on page 5 of the Monster Manual IV, which
...lists the items the creature is wearing or carrying. The expression "combat gear" appears first when applicable to remind you of other possessions referenced above.
Neither of these terms appears to be defined in the Pathfinder SRD in the section Monster Entry Format.
However, the Monster Entry Format defines the creature entry Treasure as follows:
The exact value of the creature's treasure depends on if you're running a slow, medium, or fast game. In cases where a creature has specific magical gear assigned to it, the assumption is a medium game—if you play a fast or slow game, you'll want to adjust the monster's gear as appropriate. “Standard” treasure indicates the total value of the creature's treasure is that of a CR equal to the average party level. “Double” or “triple” treasure indicates the creature has double or triple this standard value. “Incidental” indicates the creature has half this standard value, and then only within the confines of its lair. “None” indicates that the creature normally has no treasure (as is typical for an unintelligent creature that has no real lair, although such creatures are often used to guard treasures of varying amounts). “NPC gear” indicates the monster has treasure as normal for an NPC of a level equal to the monster's CR.
A severe random treasure generator is available on the Pathfinder SRD site here.
"So What Do They Get?"
When a creature's defeated, the PCs may take from the defeated creature its...
- unused expendable combat gear if any remains,
- additional combat gear,
- possessions, and
- treasure if the DM determines the creature's carrying its treasure,
but, one hopes--for the PCs' sakes--not without reason, sometimes creatures (or DMs) are jerks.
Use and Placement of Combat Gear, Possessions, and Treasure
It's possible for a creature to expend its combat gear beforehand to tilt the odds in its favor if the creature is aware of an approaching violent incursion into its territory or if the creature's planned an ambush. Such a creature leaves behind remnants of its expendable combat gear (e.g. blank scrolls, empty poison and potion vials, piles of ash from exhausted wands), much to the PCs' frustration.1 This shouldn't be constant but an indication to overcautious or blundering PCs either to take more risks or to slow down, respectively. If the PCs never could have had the opportunity to interfere with the creature using its combat gear, it shouldn't've been combat gear but a special ability or a circumstance that increases the creature's the Challenge Rating.
It's possible a creature facing certain death may attempt to lessen his killers' rewards for its doom. Such a creature may break its own gear, self-immolate, or throw itself down a pit if it knows its death is imminent just to be a jerk and deny or delay the PCs access to its stuff. Such a creature probably shouldn't've gotten to such a point in the first place, but mistakes happen. Usually such a creature should either surrender if it thinks the PCs will listen or run away if it thinks they won't, but if cornered, outmatched, and doomed, spite isn't an unreasonable response. This, too, shouldn't be constant (for example, there shouldn't always be a nearby bottomless pit for a suicidal monster to launch himself into), but if the DM is trying to encourage PCs to parley with creatures instead of murdering their ways through the campaign world, a few grim creature moments might be in order to make a point.
Finally, the DM should determine beforehand an intelligent creature's treasure if it's carrying that treasure. Such a creature may not be able to use that magic staff, but perhaps can employ that magic weapon, and it should employ that magic weapon if that weapon's better than its typical weapon. An uparmed creature is the price PCs pay for easier access to a creature's treasure.
That's because an intelligent creature needn't carry any of its treasure with it. It may have a hiding place for its treasure nearby, true, but it could instead (or also) have its treasure in its lair, buried in a random spot in the woods only it knows, or secured safely in a nearby dwarf stronghold. If, for example, a smart creature doesn't need a 1,000 gp gem, it shouldn't carry a 1,000 gp gem unless the creature just found it, received it as payment, or whatever. Finding a creature's treasure can be another whole adventure if the DM wants it to be.
Of course, a DM should only encourage a certain style of play by withholding or mitigating rewards for a creature's defeat if first talking to his group hasn't worked.
- In such cases it's perfectly acceptable for players to lament, "He drank our treasure."
James Wyatt discusses the development of Monster Manual IV's the stat block--now in use by Paizo for Pathfinder--in the Wizards of the Coast Design and Development column "Stat Blocks: Format and Function," but he mentions neither Combat Gear nor Possessions and dismisses the Treasure entry as unnecessary.