A large list of monsters sorted by their names could be found here.
Another whole page dump of monsters could be found here additionally.

The configuration files for the monsters of crossfire are usually found in the `arch' archive and svn repository. They are usually suffixed by the .arc extension.
A monster's .arc file may contain several monsters or levels. A

find -name "*.arc" | wc -l

inside the arch/monster directory of */share/crossfire/ gave me 344 counts.

So it might be better to split the monsters according to their sub-directories to not overload this page …

1. Acid
2. Angel
3. Animal
4. Beholder
5. Chaos
6. Demon
7. Dragon
8. Elemental
9. Giant
10. Goblin
11. Humanoid
12. Insect
13. Miscellaneous
14. Troll
15. Undead

The monsters in crossfire are in general hostile; especially the monsters issued by their generators. They have the

 FLAG_MONSTER		14 /* Will attack players */

set.

Other flags for monsters from server/include/define.h are:

FLAG_FRIENDLY		15 /* Will help players */
FLAG_SEE_INVISIBLE 	21 /* Will see invisible player */
FLAG_SPLITTING		32 /* Object splits into stats.food other objs */
FLAG_HITBACK		33 /* Object will hit back when hit */
FLAG_UNDEAD		36 /* Monster is undead */
FLAG_SCARED		37 /* Monster is scared (mb player in future)*/
FLAG_UNAGGRESSIVE	38 /* Monster doesn't attack players */
FLAG_RUN_AWAY		45 /* Object runs away from nearest player \
				      but can still attack at a distance */
FLAG_CAST_SPELL		52 /* (Monster) can learn and cast spells */
FLAG_USE_SCROLL		53 /* (Monster) can read scroll */
FLAG_USE_RANGE		54 /* (Monster) can apply and use range items */
FLAG_USE_BOW		55 /* (Monster) can apply and fire bows */
FLAG_USE_ARMOUR		56 /* (Monster) can wear armour/shield/helmet */
FLAG_USE_WEAPON		57 /* (Monster) can wield weapons */
FLAG_USE_RING		58 /* (Monster) can use rings, boots, gauntlets, etc */
FLAG_READY_RANGE	59 /* (Monster) has a range attack readied... 8) */
FLAG_READY_BOW		60 /* not implemented yet */
FLAG_XRAYS		61 /* X-ray vision */
FLAG_SLEEP		66 /* NPC is sleeping */
FLAG_STAND_STILL	67 /* NPC will not (ever) move */
FLAG_RANDOM_MOVE	68 /* NPC will move randomly */
FLAG_ONLY_ATTACK	69 /* NPC will evaporate if there is no enemy */
FLAG_CONFUSED		70 /* Will also be unable to cast spells */
FLAG_CAN_USE_SKILL	79 /* The monster can use skills */
FLAG_READY_SCROLL	81 /* monster has scroll in inv and can use it */
FLAG_USE_ROD		82 /* (Monster) can apply and use rods */
FLAG_READY_HORN	        83 /* unused (Monster) has a horn readied */
FLAG_USE_HORN		84 /* (Monster) can apply and use horns */
FLAG_READY_SKILL	89 /* (Monster or Player) has a skill readied */
FLAG_READY_WEAPON	90 /* (Monster or Player) has a weapon readied */
FLAG_FLAG_BLIND		92 /* If set, object cannot see (visually) */
FLAG_SEE_IN_DARK	93 /* if set ob not effected by darkness */
FLAG_NO_STEAL		96 /* Item can't be stolen */
FLAG_ONE_HIT		97 /* Monster can only hit once before going away (replaces ghosthit) */
FLAG_BERSERK            99 /* monster will attack closest living object */
FLAG_NEUTRAL            100 /* monster is from type neutral */
FLAG_NO_ATTACK          101 /* monster don't attack */
FLAG_NO_DAMAGE          102 /* monster can't be damaged */

* monsters_from_a_to_d template for a sorted name list
* monster_template template to create monster wiki entries