Saturday Video Entertainment System (SVES), on Cartoon Network
Cartoon Network Wiki; Toonami Wiki; TV Tropes
This was a Saturday night block that began in March 2003. In April 2004, it was replaced by Toonami, which moved from weekday afternoons to Saturday evenings. Honestly, I never really gave too much thought to SVES as a block, because there just wasn't much to it. The shows were good, but they would have been on with or without the block that framed them (most or all of them had aired on Cartoon Network for years before SVES debuted), and in fact when Toonami (a much superior block) replaced SVES, the lineup remained largely the same. Still, it was a block, and I watched it for the year that it existed, so I reckon I should mention its existence.
I'm not sure how much I watched on SVES in the way of reruns; probably not much at all. But I probably watched first-run episodes of ".hack//SIGN," Justice League (2001-2004), Rurouni Kenshin, Samurai Jack (2001-2004; though this may have been repeats from Friday night), and Teen Titans (2003-2006). There are also a number of shows I list on my Toonami page that I may have watched on SVES, either before or after seeing them on Toonami. I just don't remember when and where I first saw certain things, I'm afraid. So I tend to err on the side of whatever block I find most memorable. (Sometimes this means, for example, that I'll list things under Adult Swim even if I really first saw them on Toonami, whereas I might list some things under Toonami if I really first saw them on SVES or some other block or some time that didn't even have a specific block.) So... whatever. I really don't think it's that important to be certain what I did or didn't watch on SVES, though I do feel kind of bad about that.