Often enough, I do certain challenges that are familiar to me. For example, the common "no powerups" challenge on Super Mario games. The only thing that I'm sort of confused with is the question on whether or not Yoshi's would considered to be a powerup. Some say yes, some say no... I think I'd say "maybe?".
I also do a challenge on Zelda games on where you're not supposed to do get any heart containers. I see people do that all the time now, and it's a fairly easy challenge if you know what you're doing. Sometimes, it can be tricky for me in some dungeons like... the Shadow Temple? (especially the boss yikes).