wpresslucas

If you want to be able to write notes easily and quickly on the Dashboard this plugin is for you. Easy Notes is a simple and minimalistic notes plugin which makes life easier for webmasters and coders. No bells and whistles – only a simple and elegant notepad working straight out of the box.
Features 
– Simple and minimalistic. 
– Works out of the box. 
– No settings to configure. 
– Data saved in your WordPress database. 
– Accessible via the dashboard.
Do not hesitate to give feedback or request features!

Easy Notes

A very simple plugin for taking notes on your dahsboard.

shawfactor

LH Dashboard Notes allow you to insert noes on your wp-admin dashboard for your users using the post editor interface. If this plugin is network activated the insertion and editing of these dashboard notes is centralised on the main site of your multisite install. Allowing you to set Dashboard notes that are viewed throughout your multisite network.

LH Dashboard Notes

Allows you to create and edit notes that appear on the admin dashboard

Easy Notes vs LH Dashboard Notes