Leveling in Fallout 76 is now more important than ever - patch 20 gave us season system and we will get legendary perk system which needs card scrapping.
That's why you should know how to get bonus experience.
Intelligence and XP
A lot of research confirmed that INT in FO76 affects experience.
It turns out that experience math looks the same as Fallout 4 math:
Final XP = Base XP x( 1 + 0.03xINT )
That's why you should improve your INT by drugs or food.
Ways to get % bonus XP
1. Easiest way to get 5% bonus XP is sleeping.
This bonus has three variants. Each variant has increased time.
Rested (1h), Well Rested (2h), Lover's Embrace (3h)
2. Second way is Cranberry food.
Cranberry Cobbler gives us 5% XP (10% with perk card + mutation),
Cranberry Relish gives 20% XP (25% with perk card + mutation).
3. Booblehead: Leader gives 5% and last 1 hour but we can expand it to 2 hours by using Curator perk
4. Lunchbox gives us one random effect and 25% bonus XP. Best thing: you can stack them to 100%.
5. Inspirational guarantees us 15% if we are in team and have a level 3 card.
6. Last bonus (5%) is Wisdom of Mothman from The Path to Enlightenment.
More INT = More XP
Brain Fungus soup is the best for Herbivore, it gives us 5 INT.
Broiled Scorchbeast Brain guarantees us 7 INT when we are Carnivore.
2. Berry Mentats gives 5 INT and highlights an enemies.
They last only 5 minutes but we can expand it to 10/12.5 minutes by Chem Fiend perk card and BioCommMesh armor's modification.
3. Patch 20 also added Public Teams which includes Building Team which guarantees us 4 INT.
4. Armor is also opportunity to get bonus INT.
We can get +5 INT (1x5) from armor's major legendary effect.
Unyielding set which gives us +3 to all stats (except END) when we low health.
Combining these two things can give us +20 INT.
Mutations: Herbivore and Carnivore
Patch 20 changes these mutation. Now we can get 2x food's effect. Before patch Cranberry Relish guaranteed us 10% XP, now we can get 25% XP.
"How? 2x10=20" - you will say. Answer: Strange in Numbers perk card which guarantee 25% stronger mutations. That's why 25% not 20%.