Gelber Zettel adds a single square sticky note to the WordPress dashboard. The note is edited directly and saves automatically 800 ms after the last keystroke.

This is the free edition. It is deliberately limited to the essentials, and there is no paywall: features that are not included are genuinely not part of this plugin rather than locked behind a license. Greyed-out icons in the formatting menu mark features of the Pro edition; clicking one only shows a short hint.

Included:

One square sticky note on the WordPress dashboard
Directly editable text area with automatic saving
Text formatting: bold, italic, underline, strikethrough
Fixed heading: “Gelber Zettel” when the site/user language is German, “Sticky Notes” otherwise
The note is stored per user (WordPress user meta)

Only in the Pro edition (Pheme Sticky Notes):

Any number of sticky notes, each as its own dashboard widget
Color selection (5 colors plus a free color picker) and manual text color
Lists, task checkboxes, indent, font size, clear formatting, undo
Editable heading
Pin a note as a floating overlay across the whole admin area