In order to make more accessible the discovery of article and other page contents (like, wikiprojects), I propose an "always-on column" option for the Table Of Contents. The option would allow to display the TOC embed in a column inside the content space (on the left or the right side). The look and behavior of this column would be a bit like what you can see on the Wikipedia app for iPad or [[ https://www.wikiwand.com/fr/Zootopie | Wikiwand ]], except for the numbering. The column may be hiddable/colapsable.
The skin (Vector, Monobook,...) outside the main content space wouldn't be affected by this option.
Here are some screenshots I took from the Wikipedia app on iPad (you can find them with titles and descriptions in [[ https://commons.wikimedia.org/wiki/Category:Wikipedia_App | this category ]] on Commons) and the same articles on Wikiwand:
{F4575243} {F4575246} {F4575248} {F4575250} {F4575251} {F4575254} {F4575256} {F4575257} {F4575260}
{F4575631} {F4575636}