Multiple actions in one turn

[ChudoJogurt]

Are there any Su, Ex or Divine Salient abilities, feats (Epic or otherwise) or any other ways of getting a creature more than one set of full actions per round on a more or less at-will basis?
Something akin to 5e Legendary Actions, perhaps?

I am considering a boss fight of sorts for my players, and I wish them to engage one big bad guy, but I'm afraid that action economy might make it hard to have a challenging fight.
I can certainly homerule that this particular BBG just can act several times per round, but I wondered if there is an already-present thing in the rules somewhere.

[MisterKaws]

Greater Celerity and Immunity to Daze.

[Anthrowhale]

A Chronotyryn's Su dual actions ability is standard for this. Savage Species has 'multivoice' which allows you to cast 2 spells with 2 heads as a full round action. Celerity grants standard actions so Twin Celerity + Arcane Spellsurge can allow chaining to get any desired number of actions, so long as the spells hold out.

[Asmotherion]

The Celarity Line of spells can interupt an other's turn to give you actions; you get dazed afterwards but with a good build it becomes irrelevant.

in case your guy is not a caster you can give it to him as a SLA 3/day. in the meanwile be aware this is probably the most cheesy line of spells in the entire 3.5 (yes even above the Shivering touch and Polymorph line). Avoid it if you don't want to introduce your players to this type cheese.

An other good option is weapon reach; The bigger the reach the more AoO you get.

[darkela5]

ToB:The Ruby Knight WINdicator has an (su) ability that allows him to use undead turning to gain more quick action per round.
MM1: The Choker has an (su) that lets him gain extra actions per turn.
BovD:The demonlord demogorgon has an ability (ex) that let him have multiple actions per turn.


Of the top of my head those are the ones i remember.

[Bakkan]

If you are slightly flexible on the number of enemy units in the fight, you might consider having noncombatant minions (they could even be refluffed as magic items, or even Animated objects) using White Raven Tactics (ToB) repeatedly on the BBEG. This allows an alternate way for the heroes to weaken the BBEG: kill the minions, who will obviously be defended but weak once their defenses are down. As they kill more minions, their action advantage increases, but every turn spent doing so is another turn that the enemy gets to attack them.

[Biggus]

A Chronotyryn's Su dual actions ability is standard for this.

Yeah, Shapechange into a Chronotyryn (Fiend Folio). It's 3.0 but was never updated so is technically still valid. Two full sets of actions per round which can be used however you wish.

As Shapechange is 10mins/ level, with a greater rod of Extend Spell you can stay in that form all day long if you want.

[Techwarrior]

Schism, and Quickened spells in general.

[ZamielVanWeber]

Eternal Blade can get a full round action 1/encounter as an immediate.

[Darrin]

Eternal Blade can get a full round action 1/encounter as an immediate.

You could also go full-on Idiot Crusader with White Raven Tactics, but that's going pretty far into rudisplork territory. On the other hand... a group of minions with White Raven Tactics could give your BBEG a more reasonable number of turns per round, and also gives the PCs a much more manageable way to counter it: kill the minions, he gets fewer turns per round.

Some stuff that hasn't been mentioned yet... Chokers have Quickness (Su). Anthrowhale mentioned Multivoice but I actually prefer Multitasking, as each pair of arms gives you a "partial" action (i.e., a standard action). Techwarrior mentioned schism but you can pull off some action-economy shenanigans with Linked Power and synchronicity.

[Eldariel]

Temporal Acceleration/Time Stop bear mentioning. Particularly if you have Delay Spell/Power (Linked Power and Repeating Spell also sorta work) to make all those spells go off after the effect ends. But even without, Gate/Summons, Walls/Cages, buffs, etc. make said effects incredibly useful.

(Greater) Celerity can be used with Arcane Fusion or Twin Spell (or Repeating Spell) for even more extra actions.

Moment of Alacrity maneuver gives you +20 to initiative. Go to a safe place (underneath the ground is often good), delay until after your enemies have taken their turns, take a turn and Moment of Alacrity to take another one first the next round.

Belt of Battle [MIC] is obvious and awesome. All of above are limited in uses but that doesn't necessarily matter if they are used smart.

Multispell is an epic feat that enables casting one more quickened spell each turn amd can be taken multiple times. Mitigate Quicken to +0 (Improved Metamagic and its ilk; only Metamagic School Focus or Arcane Thesis eliminate the last point of cost though but Improved Spell Capacity deals with that) or RAI use Arcane Spellsurge with it (RAW it doesn't work with anything but Quicken Spell but it predatew swift action spells and swift actions entirely, so that is probably just the lack of a proper update).

[Efrate]

Whats the party level? A bunch of WRT spamming cultists worshipping their leader makes this work, you can fluff it anime style to get more power from the beliefs of your "friends". That plus belt of battle should give you enough.

[ExLibrisMortis]

Twinned synchronicity Linked synchronicity gives you four (readied) standard actions for the paltry cost of a standard action and two psionic focuses.

Contingency and Craft Contingent Spell provide extra "actions".

Besides chronotryn, Thoon elder brains have dual actions (two turns per round on separate initiative counts), but one set of actions must be used on purely mental actions, and one on purely physical actions. Serpentir (two skeletons connected at the waist with an extra handful of ribcages between) have dual actions as well (two sets of actions per turn).

Swiftblades get an extra standard action per turn at level 9. You need to be under the effects of haste, but that's easy.

Anticipatory strike lets you take your turn early.

[Xasten]

I know you already mentioned it, but I would encourage you to simply homebrew it.

Unless you want his extra actions to come from a niche build or some kind of rules heavy gimmick, the existing rules won't give your NPC enough depth of action to last for a long-drawn-out epic fight. He'll blow his extra actions, and that'll be that.

I've put NPCs as having two separate initiatives with two independent turns spaced some arbitrary number apart (say 10, so he could act on 23 and 13 during each round). I've also sometimes made their additional turn(s) have fewer actions available such as only having a 5' step and a standard on his second action and maybe only a move or move equivalent on his 3rd (if he's got a 3rd). The key is to run a few simulations and ask what is the goal of the extra actions? Is it to up the damage output? Increase his longevity or maneuverability?

Focus on why he needs extra actions and what he'd be doing with them. Once you know that, you can tailor the extra turns and exactly how they work around that goal.

Also, as an aside, it's also worth asking yourself how your players will react to custom homebrewed monsters. My players generally receive them well knowing that if they only ever faced published stats and abilities that things would get pretty stale over the years. I have, however, had a player absolutely freakout over the prospect of facing custom, non-official content, so mileage clearly varies. (He later got to stew in his choices when the other players enjoyed custom content, monsters, magic items, and such generated for them while he was stuck with his canned "official" RPG content.)

[Segev]

Are there any Su, Ex or Divine Salient abilities, feats (Epic or otherwise) or any other ways of getting a creature more than one set of full actions per round on a more or less at-will basis?
Something akin to 5e Legendary Actions, perhaps?

I am considering a boss fight of sorts for my players, and I wish them to engage one big bad guy, but I'm afraid that action economy might make it hard to have a challenging fight.
I can certainly homerule that this particular BBG just can act several times per round, but I wondered if there is an already-present thing in the rules somewhere.

What kind of boss is he? What kind of boss fight is he to present? Is he a bruiser? A spellcaster? A tank? A monster or a human(oid)? If you give us details about what kind of fight experience and narrative surrounds his presentation, we can better help you come up with ways to overcome action deficit.

For instance, there are builds that are perfectly PC-legal which can get an attack or three off against everything fighting the character every round. Robilar's Gambit and Karmic Strike combined with Combat Reflexes, for instance, can give an AoO for attacking the character, whether hit or miss.

If he's a clever or spooky sort, high Stealth and invisibility and means of breaking lines of sight can mean that he basically is only vulnerable when the party can locate him, and he can usually elude location after getting one person's actions against him off. Quasits can be really good at this if, unlike me, you remember that they can move after attacking so only the person they attacked can come after them (I messed up a fight in a module I'm running and Jot died before he got an action beyond the surprise round).

Battlefield control and trapsetting skills on home ground can lead to the environment providing extra "actions" for the villain.

Who is he? What is he? How does he engage in combat? These non-mechanical answers can help us design a believable and effective build that can deal with action deficit.

[RNightstalker]

The Dervish from CW has a class ability A Thousand Cuts that gives an additional full round action.
Time Stands Still from ToB is a maneuver that allows one to use two full attack actions in succession.
Belt of Battle from MIC is the cheapest way to do the same depending on the party level.
Doomwarding is a magic weapon ability from PGtF that allows an extra attack with the weapon each round.(maybe too simply stated on that one.)
Robilar's Gambit is a feat from PHII that gives a bonus to attack and damage to enemies but the payoff is each attack provokes an AoO. If you're going epic that can be handy with Monkey Grip, Wield Oversized Weapon, and a spiked chain.

There's also the Leadership feat that can add cohorts that may be spellcasters to help with CC from the shadows/wings, healing, buffing, etc.

[Biggus]

Imbue Familiar With Spell Ability (SpC) allows you to transfer spells of up to 5th level to your familiar who can then cast them while you do other things.

The epic feat Epic Counterspell (PGtF) enables you to counterspell any number of times per round as a free action without readying an action.