Definitely Animax CE, which could have been handled better, and SuperMax CZ - which was probably the most robust kids channel, in terms of variety, in CE to date. Maybe also Premiéra TV from Czech channels that aired many shows like SuperMax that were never rerun since.
For channels I remember watching, Qubo and to some extent Toon Disney/Jetix. For channels that died before I was born, Fox Family and Noggin(not the preschool Noggin that became Nick Jr., but the preteen educational Noggin from the late 90s and early 2000s).
I miss both Trouble and Bravo UK since for the former, I feel like it would've made a great teen-oriented channel under Sky had it not been folded a year before Sky acquired Virgin Media's TV channels and for the latter, I think it should've been stayed on instead of shutting down in the beginning of 2011.
There's one Portuguese channel I miss and it's People+Arts, which was a joint venture between Discovery and BBC and aired a mix of British and American programmes, most notably Extreme Makeover: Home Edition before it was replaced by Discovery Travel & Living, which in turn became TLC Portugal.
And for me, besides the Hungarian VIVA, I also miss the Polish one.
I remember watching it in the summers of 2009-2010 in Croatia through a digital satellite receiver. In this version, the logo changed colors after minutes, while in the Hungarian the color changed in contrast with the parts of the day. Also unlike the Hungarian one, this version didn't have any reality series (or maybe?) and counted down during ads with a transparent logo.
I quite miss a bit of Discovery Kids UK. It's a pity that the channel was shut down three years before their main American version became the Hub Network until four years later, when they became Discovery Family.
Nickelodeon GaS - Despite its later years running automated, was still a classic nostalgia spot for great game shows, even if some of them weren't on there anymore. It was definitely fun when around 2003 when I first lay witness to 'Camp GaS' for a summer long event. (in which they played Salute Your Shorts!) Don't recall if it started in '02 or maybe '01 when I first had it two years in. Some great blocks, lineups and fun commercial breaks with their own content. Fortunately having DISH, was able to enjoy it until some time in April 2009 when most(*) everyone else lost it New Year's Eve in 2007. Nothing changed when DISH carried it content-wise but in '08, there'd been some frequent errors to where the commercial breaks started with audio but then cut out the rest of it however long it added, and the on-screen bug was a little bit bigger and transparent. It was thanks to this I was able to enjoy game shows I'd never seen before, primarily due to ending close to the time I could start to comprehend, so Finders Keepers, Get the Picture, Think Fast, Make the Grade, and SK8-TV were those shows I'd not known of until I saw them here. Revisiting the classic Double Dare was a treat among all the others, with Guts + Legends topping my favorites to watch.
The Hub / Hub Network - Enjoyed its launch in a few spots 10.10.10. I didn't watch necessarily much, but when 'classic'/fan-favorite shows were broadcast, those are what I'd mostly watched. Fraggle Rock was a big one for me being able to relive that. I enjoyed their HuBoom block, and even their prime time lineup of acquired comedies and dramas. Of course, there's 2011, when a certain show began its run. Didn't see it the day it premiered but did in the next couple weeks when they played its first 6 episodes, and instantly fell in love with it, easily watching reruns thanks to its writers producing great comedy.
FOX/ABC Family - Didn't watch 'The Family Channel' at all I think when it was that, but started for sure when it was FOX Family. I recall a lunch-time lineup that included 2 episodes of Garfield and Friends an hour apart with Inspector Gadget and The Kids from Room 402 (which I never caught onto) in the middle of those Garfields. Eventually becoming ABC Family and when it was that, I enjoyed a lot of syndicated broadcasts of sitcoms like Full House, Family Matters, and especially Step by Step. None of them I'd seen in their initial runs, but Whose Line is it Anyway when they played it was my #1 fav on there and lasted a long time I recall as well as Step by Step which I loved. Pretty much when each one I watched was gone, so was I.
The N - Once again, it was shows I watched on another network I came back to for a taste of nostalgia and joy in seeing it again. Pete & Pete, Clarissa, and eventually Alex Mack. However, I did enjoy other shows broadcast ranging from Ghostwriter I hadn't recalled seeing elsewhere. I also liked one of their imports, Being Eve. I didn't see 24Seven much but I know that was there. Also really enjoyed A Walk in Your Shoes. At the time I first saw The N, they were only broadcast from 6pm-4am I think, maybe 3. After the block and before Noggin started up, they had a 2-hour Cable in the Classroom block with a few different shows each getting their own 2-hour spot each week. Bill Nye the Science Guy was among those shows including a few I'd never heard of, 3-2-1 Contact for example, though as much fun as it was watching Bill Nye again, became the only of those shows I caught, and even that wasn't much. Later on when The N had expanded to a full 12-hours, I remember other imports and other teen-based shows they did. Many I didn't watch, but it was a great feel for the network, and they belonged. That's when it 'was' teen shows. They also had a reality competition show called Boys vs. Girls which was enjoyable. TeenNick now sadly can't compare to that at least in regards to the channel name. Many of those shows were 'tween' targeted I'd say. While yes, I enjoyed some of those too, it's still the name of the channel that doesn't make them feel in place, though perhaps teenagers when some of those shows were broadcast originally (in which I was before High School grad), still fits from their demo. Just not the same like it used to be with The N though. (I type mostly this, but not my favorite listed here) -------- I don't really have much to say for Noggin as I had watched a few shows, but only for nostalgia, and I think just two. Little Bear + Gullah Gullah Island.
G4 - I really didn't watch this one all that much - at least not until it had become that from TechTV, but I did for a few anime, and IIRC, didn't stick to completion on any of them. I wish I had in a way, but also it may have been due to a lack of interest in the anime itself. Kind of most of what [as] played had more of an interest in, and no matter what G4 got, seemed I couldn't get into it. I wish I tried better but couldn't force myself to try something not interested in. Do wish I payed a little more attention to those superhero anime they'd broadcast like Iron Man and etc. They were plenty on weekends close to the end of G4's broadcast life.