Here are some ideas for non-standard 'Increased XP by %% for next X days!' options:
Submitted on Dec 28th 2020 by Guest
1) Roaming mob/titan (like Santa) that when killed gives you a % of your overall Character XP instead of standard 'Titan/Mob' amount (could be like 10% or something)
2) Instead of gifting AC (which is awesome!) or other things (on those 'present' days), you could also gift a % of Character XP. (e.g. 5% of total Character XP gifted).
3) After earning a certain % of Character XP, you are granted a buff for the remainder of the day towards XP earning (e.g. Character has 1T XP and you earn 250B, so you gain 10% more XP for remainder of day, etc)