Here's the list, they're mainly intended to be used with a new character from level 1 and playing through the game and these challenges are in no particular order and you probably shouldn't do them all.
- Don't do either 15 attribute quest
- Don't use runes or mask that gives +1
- Only get armor and weapons from collectors
- Don't swap campaigns until you have a protector title
- Don't get infused
- Leave that plauge stuff on you that gives you degen
- Limit your party size to 2 less than the maximum allowed in
- Only use skills you obtain from quests
- Only use skills from your primary profession
- Only use skills from your secondary profession and with or without points in your primary attribute
- Don't ever get new armor or weapons (if you're a caster or ranger this is easier)
- Don't wear a head piece
- Don't wear + energy regeneration part(s) (must rely more on signets, adrenaline and energy management)
- Wear all superiors at all times (not duplicates, just one of each, including vigor, unless you're risky and want to play through as a 55 or something)
- Don't use an elite skill
- Don't bring a full skill bar
- Limit how many points you can put into an attribute
- Limit how many different attributes you can use
Now I know a lot of people might be thinking this is just a good way to screw over your team mates, but when I had my friends doing the same thing it was a really fun challenge to get on every day, get the team together and work on completing a mission or doing a primary quest. Have fun!