Nickelodeon's former programming blocks SNICK and TEENick had their own distinct logos. The current TeenNick channel also has its own logo, as well as the throwback block last known as NickRewind.
Nickelodeon's preschool block Nick Jr. has had several logos since it launched in 1988, the most recent of which was carried over to its own 24-hour channel.
1988 Pre-Launch Logo
1988-2009 wordmark
1993-2003 logo
nick jr. 2 (2006-2010 logo)
Birds
Toucans
Australia Logo
1995 Grabbing Son Logo
Nick Jr. on CBS (2000-2002)
2002 Hugging Logo
2003 Butterflys
Stars
Circles
2003 Mice
2004 Lions
2004 Dogs
2003 Frog logo, commonly seen in the opening of Nick Jr. DVDs
2004 Armadillos
2004 Horses
2005 Raccoons; this was used as the Nick Jr. On Demand logo and the on-screen bug for split-screen credits
2006 Elephants
Teddy Bears; this was used as an on-screen bug from 2006-2008.
2006 Bats; there is also an on-screen bug with this during Halloween
2006 Ghosts; there is also an on-screen bug with this during Halloween
2006-2009 Grabbing Son Logo
Plush Beardogs
Plush Bunnies
Plush Robots
Plush Scaters
Plush Space Monkeys
A color swapped version of the logo (2000s, unknown, LQ)
Noggin, a channel created by Nickelodeon and Sesame Workshop, launched in 1999 with its own logo. The channel also used logos for its nighttime blocks, The Hubbub and The N, respectively.