crimson090

Adds buttons to the Text (HTML) edit which generate Markdown syntax. These buttons serve as a great introduction to 
users who are new to Markdown, as well as shortcuts for more experienced users. The buttons include:
<ul>
<li>Bold</li>
<li>Italic</li>
<li>Blockquote</li>
<li>Link</li>
<li>Code</li>
<li>Table</li>
<li>Headers</li>
<li>Help (links to external Github Markdown guide)</li>
</ul>
This plugin does not modify the Visual editor, as that editor is not ideal for writing Markdown in. It’s recommended you disable 
the Visual editor entirely to enforce using Markdown.
Note that this plugin does not render Markdown. You should use a plugin (such as Jetpack Markdown) to render markdown in your theme.

MarkdownBar

Adds a toolbar of buttons to the Text (HTML) edit which generate Markdown syntax

Rich Tabor

<h4>Editor-friendly blocks</h4>
While diving into this project I’ve explored a few areas where I can improve my personal publishing flow. The first was bringing editor comments into Gutenberg with my <a href="https://richtabor.com/markdown-comment/?utm_source=wp-org&utm_medium=todo-list-block&utm_campaign=readme" rel="nofollow ugc">Markdown Comment block</a>, and this Todo List block.
Todo List is a simple, editor-only block designed to quickly add tasks directly within the editor.
Todo List makes it easy to keep track of those tasks, all in the context of a particular post. You may also use it to add a publishing checklist to the post, such as using a headline analyzer, adding featured images, adding social images, etc.
<h4>Transforms</h4>
I’m a huge fan of blocks transforms and how they improve the WordPress publishing experience. Being able to morph a block into another, without loosing content/attributes, is a powerful way to level-up editing.
That saying, you may transform paragraph text, list items and even editorial comments added by Markdown Comment directly into actionable todos, just like you can in the iOS Notes app for example. You may even take multiple blocks of the sort and convert them all into a single todo list.
Todo List also supports block prefixes, which are keyboard shortcuts in a sense, to toss blocks in the editor with a few keystrokes. Adding <code>[]</code>, or <code>-[]</code> plus the <code>space</code> key will add a Todo List to the page.

Todo List Block

It works as advertised, I just wish there were some more features such as:

- Font size & font color options (per list item).
- Option to also display on the front end.
- Option to indent each list item, so we can have "category" items. This (maybe) would  not be necessary if we had the choice to change the font color and size per list item.

On the other hand, this plugin as it is, is still very useful, and the zip file is only 16kb, so adding things in and multiplying the file size by a a lot, may be it won't be worth it.

Nevertheless, I am sticking to my 5 star rating for this.

Good Start.

Add todo lists to posts that render only within the block editor.

MarkdownBar vs Todo List Block