The logseq plugin samples page is missing something – how would someone implement a sidebar? In particular, how could you build a component like the graph that uses data about the current page?
I’ve heard of a number of other features requesting sidebar components that refer to the current page, for example requesting a TOC, page specific task list.
The journals calendar sample is closest in overall capability, but it does not render in the sidebar and it does not do anything different depending on the current page context.
An example doing this would enable community contributors to build these kinds of enhancements.
Looking through, I believe the best solution would be to tap into the macroRenderer and create it programatically on some random page and then open this block in the sidebar. I think these two TOC plugins are the best option.