Cudazi

Adds a smooth scroll to top feature/link in the lower-right corner of long pages. Appears after a set scrolling point and hides after scrolling near the top.

Cudazi Scroll to Top

Adds a smooth scroll to top feature/link in the lower-right corner of long pages.

wenzizone

在页面的左侧或者右侧创建一个“返回顶部”的按钮，使用“返回顶部”按钮，可以方便快捷平滑的返回到blog的顶部。
This WordPress plugin adds an “Back To Top” button to easily scroll long pages back to the top.

BackTo Top Plugin

Back To Top Adds an "Back To Top" button to easily scroll long pages back to the top.

Cudazi Scroll to Top vs BackTo Top Plugin