I'm not sure if this has been submitted yet, but for writing- and media-centric sites it might be helpful to have a tool for easily and quickly creating collapsibles, for "spoiler" tags, "fourth wall" tags, or other things which we might want to keep hidden away unless a reader particularly wants to read them at that moment. I know how to make those things manually, but many of the other users I'm inviting to my site don't and my work schedule is too full for me to keep telling everyone how to do it every time.
This is good suggestion. I'm voted.
Technical Staff of SCP-JP
Technical Staff of 보카로 가사 위키