Question: I often find myself changing text colors to the same color for five minutes at a time which is really unnecessarily mouse-intensive.

Answer: 
The answer is **no** for:

> 
> shortcut key for changing text color to the last color?
> 
> 
> 

but you can always make one for color change:

* first you will need to click on the toolbar/ribbon to escape the cell

[![0](https://i.stack.imgur.com/RI50A.png)](https://i.stack.imgur.com/RI50A.png)
* now use this combo:

---

 10x +  15x +  3x + select color
================================
* now you can use something like **[AHK](https://www.autohotkey.com/)** to save this combo (including that initial click) under one key. for example:

	+ red color under **F7** key: **```
	click + tab (10x) + right arrow (15x) + down arrow (4x) + right arrow (1x) + enter
	```**
	+ reset (black) color under **F8** key: **```
	click + tab (10x) + right arrow (15x) + down arrow (1x) + enter
	```**
1. Copy the cell that has the formatting that you need (Ctrl+C)
2. Paste format only on top of the cell(s) that you want to be formatted the same way (Ctrl+Alt+V)