Most items coming from questions on the community forum

• a proper multicategory bar example based on https://community.plotly.com/t/multicategory-axis-type-example/26392
• example of shape or annotation covering several subplots thanks to xref='paper'. Also the shapes and annotations tutorial should link to each other.
• orthographic projection example in 3d axes tutorial (or 3d camera controls)
• improve explanations on updatemenus and changing animation speed in animations. See https://stackoverflow.com/questions/59070876/plotly-how-do-the-buttons-for-the-update-menus-really-work/59076340#59076340, https://community.plot.ly/t/scatter-animation-doesnt-work/31944 https://community.plot.ly/t/need-animation-example-with-scattermapbox/9720/10 https://community.plot.ly/t/how-to-slow-down-animation-in-plotly-express/31309/7
• in slider page https://plot.ly/python/sliders/, add example using the update method (modifying both traces and layout), as in the buttons tutorial https://plot.ly/python/custom-buttons/, and also an example using relayout. Discussed in https://community.plot.ly/t/update-plot-with-restyle-method-get-the-current-selected-slider-value/36162/4.
• example using px.strip, see https://community.plotly.com/t/make-a-violin-plot-with-only-points/37412/3. In box plot page, and add a link also in violin page.
• example of sparkline in scatter and line page. See this community post.
• example using surfacecolor in 3d surface tutorial. See this community post.
• example of how to use go.Frame to target only certain traces in updates Underlying plot data dissapears when animation frames are added #2423 (comment)
• example of how to use mapbox sourceattribution
• example of update_scenes and clarity on how update_xaxes is 2d only Updating layout of specific subplot  #2483 ... similarly let's ensure there's an example somewhere in the docs for every update method: polar, ternary etc
• we need an example of append_trace somewhere, even just to say it's equivalent to add_trace except that it doesn't return the figure (for... reasons?)
• would be nice to have a demo of a facet grid map like this one: