Increase Taskbar Transparency Level
1. In Registry Editor, go to following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced
2. In right-side pane, create new DWORD UseOLEDTaskbarTransparency and set its value to 1
3. Restart, log off or restart Explorer as given here to take effect and it'll make Windows 10 Taskbar more transparent.
If you want to restore Taskbar default transparency level in future, delete the DWORD UseOLEDTaskbarTransparency.