This list of abilities is primarily oriented to fantasy but with a little tweaking can be used in other genres. Mostly you are going to be using them with a boss monster with a bunch of mooks, a bugbear and a bunch of goblins or orcs is a perfect example. Dragons, ogres and giants all also make good warlord types. A boss using these abilities will usually stand out but this doesn't have to be the case, Care must be used in assigning these as your goal should always be a challenging encounter and not a TPK. Where these abilities originate are at the Keepers discretion: Intellect, supernatural leadership, charisma, commanding presence or my favorite go to, "It's Magic!"
This boss grants additional attacks to his mooks. He gives up his action and commands another of his group to attack. This can be anywhere from one additional attack to all of the group gets an attack on the boss's action and their own
After a failed morale check, this warlord tries to steel his legion, granting an additional morale check to avoid breaking and running. If the second check is made, perhaps a bonus or penalty is in order: Uriki might get a small bonus to hit for a couple of rounds, Ogres might get a small bonus to damage, while goblins might be left shaken and have penalties.
"THEY ARE ALL PUPPETS"
A warlord with this ability is normally a frontline fighter and uses his compatriots as meatshields. Any attack that would ordinarily hit him, instead the damage is passed on to the mook. This may or may not include spells and the mook might take more or less damage than would normally be assigned
"DO BETTER OR ELSE!"
When one of his mooks miss, they are granted a reroll, sometimes at a bonus or penalty..A good visual for this is to give the warlord a long whip that he either cracks or strikes the hapless mook. Warlords with this ability are often in the back of the fight ( a frequent ability for goblin or kobold warlords).
WOLF PACK TACTICS
Coordinating several mooks on a single foe, a bonus to hit, damage or both is attained. This can also render a disarming, tripping or sundering attack on the foe's weapon.This can sometimes be used to initiate a grapple, possibly without the normal penalties for starting such an attack vrs an armed foe.Another good ability for smaller sized mooks.
The mooks are organized in such a way that their shields are over lapping and a defensive bonus is granted. Not necessarily an option for shield wielders only, sometimes groups with long spears and other two handed weapons can achieve this bonus.
The mere example of the warlords standing on the battlefield inspires his mooks to greater en devour. Any combat bonus is possible. Normally associated with a front line, high charisma or terror inspiring boss.
PIN POINT STRIKE
While most of these abilities tend to be melee oriented, this ability applies to missile weapons. Several archer types are coordinated in an accurate volley fire. Special troops can be trained to disrupt spellcasters specifically.
This warlord is able to quickly replace combat losses with effective recruits.
"WE ARE ONE"
Many different types of monsters flock to this warlord's banner. Even monsters that are diametricly opposed to each other will follow this inspiring leader. Some are even able to command strange beasts such as giant spiders or ants and rust monsters
Additional Ideas (1)
The main villain keeps his mooks in a crescent shaped formation so that if the PCs have to close in to fight with swords, they will quickly be surrounded on all sides as the "horns" close around them.
The PCs are dealing with changelings aka MLP. Not only can they look just like the PCs, making friendly fire a possibility, but the main villain has a "Leach Love" attack once every three combat rounds that leaches HP and Skill points from the PCs if successful.
The bad guys are dressed as city guards, paladins or other "good" guys and get in a free strike on the PCs before battle commences.