Alphabet

Here is an undated video of a Sprout bumper, regularly used before commercial breaks.

Here, we see letter swings and kids appear in letters, then the green Sprout in the logo slides down a J to the rest of the logo.

It was replaced by the box idents in 2009.

Image from Facebook

Apparently a picture of the Alphabet ident remained up in Sprout studios in Philadelphia as late as 2014.