When you’re grinding out reputation for hours, days and weeks on end, every possible bonus helps. Think of this as stacking haste for your reputation grind.
These are all of the currently available reputation bonuses. Most are only available during certain times of the month or the year. Most reputation bonuses stack with each other, so if you have two 10% bonuses and a 5% bonus, your overall reputation bonus will be 25%. With a 25% bonus, a quest that normally grants 500 reputation will grant 625 reputation.
Humans automatically receive a 10% bonus to reputation from the Diplomacy racial passive ability.
If you aren’t a human and you’re on an extended reputation grind such as Insane in the Membrane, it may be worth changing your faction/race for the duration of the grind.
The Banner of Cooperation / Banner of Cooperation grants a 5% bonus to reputation from killing monsters. Obtaining it requires that your guild have earned the achievement Working as a Team by reaching 525 skill in every profession and earning Friendly reputation with your guild.
The Standard of Unity / Standard of Unity grants a 10% bonus to reputation from killing monsters. It’s available once your guild has earned the guild achievement Guild Cataclysm Dungeon Hero and you have earned Friendly reputation with your guild.
Once your guild has earned A Daily Routine by completing 15,000 daily quests and you have earned Friendly reputation with your guild, you can purchase the Battle Standard of Coordination / Battle Standard of Coordination which grants a 15% bonus to reputation from killing monsters.
Battle standards can be purchased from any guild vendor.
Note that the battle standards do not increase reputation gained from turning in quests. They also despawn if the person who dropped them moves more than 100 yards away from them.
This world event runs one week each month beginning on the first Sunday of the month.
There are two ways to get a 10% reputation bonus from the Darkmoon Faire. Unfortunately they are mutually exclusive and do not stack with each other. So you can only use one of them at a time.
Ride the Darkmoon Carousel at the Faire to receive WHEE!, which grants you a 10% reputation bonus for 5 minutes. Stay on the carousel and the buff duration will increase, until it maxes out at one hour. Then hop off and head out quickly to earn your reputation.
Or, buy a bunch of Darkmoon Top Hat and take them with you. Using one of these grants you a 10% reputation bonus for one hour. The hat is an uncommon reward from a Darkmoon Game Prize, or you can buy them from Gelvas Grimegate for 10 Darkmoon Prize Tickets each. But don’t buy too many of them; they only work during the Faire week and will be lost after the Faire closes.
This is currently the most powerful reputation bonus as, due to an implementation issue, both of these buffs grant more than double (over 20%) reputation bonus to mob kills. This bug may be fixed eventually, but for now it makes the Darkmoon Faire buffs nearly mandatory for any serious reputation grind.
This world holiday runs two weeks from October 18 to November 1 each year.
Alliance players should visit the Wickerman outside the front gates of Stormwind and right-click on the bonfire in front of it to receive Unburdened, granting a 10% bonus to reputation for two hours.
Horde players should visit the Wickerman in the Ruins of Lordaeron in Undercity and right-click on the ashes on the ground near it to receive Grim Visage, granting a 10% bonus to reputation for two hours.
The Wickerman only grants its buffs if it is burning. If the opposite faction has put it out, you must relight it yourself by right-clicking on the bonfire in front of it.
This world holiday takes place near the end of November and runs for one week with varying dates each year. In 2017 it runs from November 20 to 27.
Every town with an innkeeper has a set of Bountiful Tables. Sit at each of the five seats at a table and stuff yourself with five stacks of each food at each seat. This will give you the buff The Spirit of Sharing, granting a 10% reputation bonus for 1 hour.
This world event takes place in November and runs for two weeks with varying dates each year. In 2018 it runs from November 16 to November 30.
Since 2011, Blizzard has celebrated WoW’s anniversary by mailing players an item which grants you an experience and reputation bonus. Check your mail and pick up the Celebration Package, which in 2018 grants a 14% bonus to reputation from mob kills for one hour each time it’s used. The item will disappear on or after November 30, 2018 when you log out or cross a zone boundary.