Level 1, Lasting Full-Party Buffs

[Axoren]

Morale: A party having access to Flagbearer gets +1 to attack and damage (plus some other stuff) indefinitely (30 ft).
Competence: A party having access to Lingering Performance Inspire Courage gets +1 to attack and damage (plus some other stuff) for 3 rounds.
Untyped: A party with a Divine Domain Cleric gets +2 to their next attack roll (or their next other stuff) whenever the Cleric is the target of a Divine spell (15 ft).

Are there any other attack/damage buffs a party can drop (affecting everyone) with minimal resource expenditure that will stack with the above at level 1?

Minimal resource expenditure being that they can be expected to have remaining uses after a single combat at early levels.
- A Lingering Performance Bard would only spend 1 Bardic Performance use on a fair encounter lasting 3 rounds. They generally have over 5 uses per day, and get more each level.
- A Flagbearing Bard would spend absolutely no resources providing their Flag bonus.

[Axoren]

Something to add to the list.

A Divine Domain Cleric can give +2 to all allies' next attack rolls by casting Guidance or Resistance on themselves (untyped). Alternatively, they can have a divine spell cast on them by someone else to proc the effect.

So far, that's a total of +4 to Attack, +2 to Damage.

[Axoren]

Bump. Are there any others?

[Lord Foul II]

Aid another can be preformed to give bonuses to hit or to AC and familiars can do that for you
A valet familiar can cast guidance once per combat if I remember right
Um...Mage Armor lasts for an hour, longer with a Mage tattoo

[Axoren]

Lord Foul II wrote:

Aid another can be preformed to give bonuses to hit or to AC and familiars can do that for you

A valet familiar can cast guidance once per combat if I remember right
Um...Mage Armor lasts for an hour, longer with a Mage tattoo

Generally all those buffs are single-target, getting them on the whole party is unreasonable. Are there any more buffs that affect the whole party in one action?

[BadBird]

If you go Flagbearer + Banner of the Ancient Kings on an Evangelist Cleric instead of a Bard, you can cast Archon's Aura (1min/level) and Aura of Doom (10min/level) to continually cripple everything in a 20-foot radius, which is essentially a party-wide buff.

Persistent Archon's Aura in particular is really mean, as enemies lose -2 attack, AC and saves. It's arguably best used on a more tanky Evangelist though, since the effect ends if you get hit. A Fighter 1/ Evangelist in heavy armor that's simply carrying the Banner on a pole in the same hand as a light shield is pretty hard to hit, especially with Archon's Aura and Aura of Doom stacking -4 on enemy attacks.

[Markov Spiked Chain]

Freebooter Ranger has Freebooter's Bane for a +1/+1 against a single target.
Arguably, Combat Advice is long term at level one, since you can use it every round without much loss.