I really love the transparency effects Microsoft developed on Windows 7’s Taskbar. Even the ones on Windows 8.1 or early build of Windows 10 are not bad. But I just feel it’s not transparent enough on the recent version of Windows 10. So is there any way to make my Windows 10 Taskbar more transparent?
First, enable the Transparency setting
Open Settings app, go to Personalization and Colors and turn on the Transparency effects setting there.

If you’ve already done it but see little change, let’s move on to the next step.
More transparency through Registry
Open Registry Editor, navigate to the following location:
HKEY_Local_Machine\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
Then create a new DWord (32-bit) Value, name it as UseOLEDTaskbarTransparency, and set its value to 1.

Toggle the Transparent Effects setting off and on in Settings to activate the change.
What about if it’s still not enough?
A 3rd party tool
TaskbarTools is a portable free tool that can make your Taskbar fully transparent and add blurry if you like. Download the tool, extract it and run the executable to launch the tool.

Use the slide bar to change the level of transparency you like to set and set it to start with Windows under Options when ready.

As you can tell, now I am very satisfied with how transparent my Taskbar is.