In the late 90s and early 2000s, PBS Kids released some TV spots that aired in between shows. Many of them are found, although in low quality, but some are lost, especially the animated spot with the boombox boy.
Bear at the Campfire (aka Bear and Friends, Honey Bear, What Happens Inside, and Bald Man) (Found)
Two kids imagine a story about a bald superhero and king. A bear joins them, but has honey on his mind. (FOUND)
Boombox Boy and Crying Girl:
An animated spot featuring a crying girl and a boy playing hip hop on his boombox to cheer her up. (FOUND)
World Wide Web:
Kids learn about the Internet (circa the early 00s), then DW Read of Arthur fame shows up with a surfboard, ready to "surf the web". (FOUND)
Clifford the Big Red Dog has his nose stuck in a playground tube, and kids work together to get him out. (FOUND)
Rapping/Dancing TV with Teddies:
A dancing TV raps about exercising, while teddy bears join him. (FOUND)
Ask for Help Song:
A girl gets cranky when she can't reach the faucet and others help her. (FOUND)
Kids Are Rap Song:
A rap about kids. (FOUND)
Talking Tree (FOUND)
It shows a tree and 2 birds talking. A soda can falls onto the ground and everything was sad. 2 kids (one boy and one girl) looked at the soda can and the boy grabbed the can and threw it into the trash and everything was happy again. A female voice was saying E malama i ka aina (Take care of our land), while the tree smiled (This bumper is Hawaiian).
Gimmie Five Rap Song (FOUND)
A rap about the food groups.
This Is Your Brain On Books (FOUND)
A take on the famous This Is Your Brain On Drugs campaign, only this time, books are used in place of eggs in a frying pan and drugs. (Though a frying pan and eggs are used, they are not being fried. Books are shown in the pan instead.) It shows the three "C's". Creating (Building), Computing (Numbers and Symbols), and Composing (Musical Instruments). At the end, a house is shown, and there is a voiceover asking ANY QUESTIONS? The beginning shows an egg being dropped into a human's head and the egg cracks along with falling into the pan.
Curiosity Killed The Cat (FOUND)
A cat walks and a trash can appears to the words and a cat jumps to the trash can and the cat wants a kite and a lighting zaps to the lightbulb. The voiceover at the end says Curiosity, It's Electrifying! Real meaning of the commercial is here. https://www.google.com/search?q=curiosity+killed+the+cat&oq=curiousity&aqs=chrome.5.69i57j69i65j0l4.6159j0j7&sourceid=chrome&ie=UTF-8
Spanish Colors (PTV) (Partially found)
Cora And Her Lamb (Found)
What's In A Painting? (Found)
Another rap song, but this time, it's asking what is in a painting. Has the sound of a ticking clock at the beginning.
UPDATE 9/1/16 #2: User BunderThunder has asked many people on YouTube if they had these bumpers. Some said they didn't have it, others say they don't remember them, especially Boombox Boy. If you remember these bumpers and might have them to upload in high quality, please comment below! -BunderThunder
UPDATE: 9/1/16 #1: Bear at the Campfire, World Wide Web, Teamwork Song and Rapping/Dancing TV with Teddies were found and circulated on YouTube, but are of low quality due to being camera recordings of TV screens, with the subtitles in the way. User BunderThunder has asked the uploader of Bear and Rapping TV, amer l, if he could upload the videos in better quality, but he hasn't replied. User PBSfanatic probably has Teamwork and Web, and we hope he can upload them! PBSFanatic also said he does not recall Bear, Rapping TV, and Boombox Boy. -BunderThunder
UPDATE: 9/9/16: A good quality of Bear at the Campfire has been found. Found by Satoshi9801.
UPDATE: 9/21/16: Boombox Boy and Crying Girl has been found. Found by PBSfanatic.
UPDATE: 10/24/16: A good quality of World Wide Web has been found. Found by PBSfanatic.
UPDATE: 1/19/17: A good quality of Rapping/Dancing TV with Teddies has been found. Found by Phoebe Thunerman.
UPDATE: 2/11/17: A good quality of Teamwork Song has been found. Found by PBSfanatic.
https://www.youtube.com/watch?v=0R1y8sYKfdQ (Skip to 2:45)
UPDATE: 3/30/17: Ask for Help Song has been found. Found by RTXwheels.
UPDATE: 4/18/17: Kids Are Rap Song has been found. Found by Rewind Eats the Tape. (Note: I know this was found on April 18, 2016, but this is the first time I saw it)
UPDATE: 5/11/17: The full Boombox Boy and Crying Girl spot has been found. Found by RTXwheels.
UPDATE: 5/11/17: the talking tree bumper was found by DGBarneyFanatic
https://www.youtube.com/watch?v=Cxvvq-THfxo skip to 28:58
UPDATE: 8/4/17: the full ask for help song was found by BCHsface