Minimax (partially found identity package; 1995-2006)
Minimax is a children's channel that originated in Spain and has spread to Eastern Europe. It currently airs in Romania, Hungary, Serbia, The Czech Republic, and many other countries. It has also aired previously in Poland, and there are reports that it aired in the UK. The channel's current identity package, which is from 2013, is an updated version of the 2006-2013 identity package.
History of the 1995-2006 Minimax Identity Package
The 1995-2006 identity package is, in fact, the channel's second one. The original package was very different.  The second package was most likely implemented in 1995, but the farthest back footage was from 1997. It is only recently that there has been actual evidence confirming the identity package survived 2 years into the third logo (which was in 2004), and there seemed to be evidence of the third identity package being released at that time.  (Notice that the characters are from the third identity package) It wasn't until 2016 with the release of Sirokman David's ident compilation that showed idents with the new logo.
For a while, it was previously thought to have been introduced in 1996. On August 28th, 2019, a poster with 5 of the mascots dating back to 1995 was found on a Spanish forum, thus dating the identity package back to 1995 as well.
A notable thing about the identity package is that it is technically three different packages from three different groups, with a possible fourth group in Poland. The first group's idents had the most "surrealism" to them, often went "off-model" (possibly intentionally a la Ren and Stimpy) and had a group of voice actors whose roles were inconsistent.  The second group looked like the first, but the models were more consistent, and the voice acting was possibly pitched up.  The last one had an almost completely different art style, and some idents were made with the new logo in mind.
Possible Identity of Package Designer
Another thing to note is that it seems that only one group on the web has claimed to have worked on any set of the idents. This is a list of candidates for just the original designer.
Martin Lambie-Nairn - Possible but Unlikely: The Wikipedia article for Minimax once claimed that "The first look was designed, animated and directed by Martin Lambie-Nairn in 1996." However, the only other web pages claiming this was copy-pasted of the article in question, and it was removed on the second of March in 2016.  A tweet asking whenever to confirm or deny the claims went unnoticed. 
Francesc Capdevila aka "Max" - Disproven: A commenter on Reddit said that the idents looked similar to the art style of Capdevila.  However, when asked about this on Facebook, he claimed that he did not work on them. He gave no reply on if he knew who did. 
Peer of "Max" - Possible: It would explain why the art styles are similar. Max himself has neither confirmed nor denied this.
Ostra Delta - Highly Likely: Ostra Delta is said to have worked on Minimax.
Juan Delcan - Highly Likely: Worked at Ostra Delta as creative director between 1988 and 1994 (which implies that the package came much earlier than most expected). He also uploaded an ident onto his Vimeo channel  and has footage of a character similar to one of the characters in his animation reel.