Currently, events in DSA have quite an uneven release schedule. This graphic below does it's best to guess when an event will come back. With time, and more consistency, this will become more accurate. New events are added very frequently, so make sure you check back later to see if things change.
Note: Events in Disney Sorcerer's Arena are becoming more and more spaced out. The daily average continues to grow in between events. Events with only 1 "run" use the total average, while events with more than 1 "run" use their own average to calculate when they may return.
Sally's Potent Potions
Scrooge's Money Bin Heist
Intergalactic Rune Rumble
Sorcerer Stone Events