Just a little something I wanted throw out here based on a conversation in map chat earlier: be sure to buff up as much as possible before doing your orphan run to maximize the amount of karma you get!
Food buff - I always recommend ascended foods here, but if you don’t have access to any, these are also recommended: Peppermint Omnomberry Bar, Tropical Peppermint Cake, Scoop of Mintberry Swirl Ice Cream, or Plate of Island Pudding
Utility buff - Peppermint Oil, Tin of Fruitcake, and Tuning Icicle are great examples
Amulet enrichment - Karmic Enrichment available from laurels is most common, but there is also the Koda’s Warmth Enrichment which is a LS3 collection
Guild Hall buff - This is anywhere from 3-10% depending on how many enhancements the guild has unlocked
Guild Banner buff - A Guild Karma banner gives 5% whereas a Guild Karma and Experience banner or a Guild Heroes banner give 15%
Spirit Banner buff - Gives an extra 10%, grab these from Miyani in Lion’s Arch or any Mystic Forge NPC
Booster/Bonfire/Gobbler buff - An additional 50% Karma Bonus can be gained through a communal bonfire set to Karma, a random Gobbler buff, or a Karma specific booster
Winter’s Blessing buff - You get this hour-long buff from giving gifts to the orphans; I always use mine right before doing my orphan run!
Candy Cane buff - Each one you consume gives you an additional 10% karma boost, stacks up to 30 minutes
Volunteer’s Blessing buff - Rare, but can happen if a map gets low enough, and gives you an extra 5% karma for 10 minutes
Race buff - This one you can get from the race event or by doing the trial, and gives you an additional 10% for 15 minutes
My advice: do the Race event or time trial first, then buff up, then do your orphan run!