Oren Yomtov

1.7: 
WordPress 2.9.1 compatible.

This plugins allows you to add your own buttons to the post edtor’s toolbar. 
I’m talking about the buttons that you see above your content text area when editing posts (b,i,link,img,ul,li). 
For example you can add a “h3” button to make subheaders in your post. 
There are virtually endless buttons you can add.

<a href="http://orenyomtov.com" rel="nofollow ugc">Yomtov</a>
<a href="http://twitter.com/orenyomtov" rel="nofollow ugc">You should follow me on twitter</a>

Post Editor Buttons

This plugin allows you add your own buttons to the post editor's toolbar.

Homer WP

🧰 Block Editor formatting tools to give you more control over your content.
<h3>Formatting Features</h3>
<ol>
<li>
Text change animation 🔁
</li>
<li>
Inline icons library (with gradient)
</li>
<li>
Emoji library 😉
</li>
<li>
Tooltip popover
</li>
<li>
Special characters library ❁
</li>
<li>
Screen reader content
</li>
<li>
Language attribute 🌍
</li>
<li>
Hidden text / Spoiler
</li>
<li>
Uppercase text
</li>
<li>
Lowercase text
</li>
<li>
Capitalize text
</li>
<li>
Underline text
</li>
</ol>
<h3>How to use</h3>
<ol>
<li>
Go to post or page where Gutenberg editor is enabled.
</li>
<li>
Select the word you want to format.
</li>
<li>
Open more formats via clicking the “Homer Formats” button.
</li>
<li>
Choose the effect you want to apply.
</li>
</ol>
⚙️ Universal: With this plugin you can add these effects to the text of almost any Gutenberg block, which is not limiting it format options.
⚙️ Animations: You can choose one of the types of animation that best suits your design, and change the settings to achieve the desired effect.
⚙️ Completely Customizable: You can customize the content, speed, etc to make it suitable for your website design

Homer – Block Editor Tools

Does what it says, and it does it perfectly !

Well done, and thanks. 

Really good.

🧰 Block Editor formatting tools to give you more control over your content.

Post Editor Buttons vs Homer – Block Editor Tools