DC Nation, on Cartoon Network
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This was a Saturday morning block of shows based on DC comics. It debuted in March 2012, and ended sometime in 2014, but since I haven't had Cartoon Network since June 2011, I never got to see it, which really bums me out. (I'm not sure that the block actually replaced any specific block on Saturday mornings, though for the last few years before I lost the channel, there were generally repeats of shows whose episodes premiered the preceding night in the Action Fridays block, as well as a few other shows whose episodes premiered on Saturday mornings, such as Pokemon and Super Hero Squad Show.)

The DC Nation block included the latter part of the first season, and all of the second season, of Young Justice (2010-2013), a show that originated on Action Fridays, so I saw the first several episodes of the series. The other series in the DC Nation block, "Green Lantern" (2011-2013), the first season of "Teen Titans Go!" (2013-present), and "Beware the Batman" (2013-2014), I have never gotten to see at all.

There were also a bunch of interstitial shorts that aired during this block, some of which I eventually saw online. (I watched them on the DC Kids YouTube channel, though that didn't have every episode of every series, so for some of them I'm linking to different YouTube playlists that do have all the episodes.) The ones I saw included:

Amethyst: Princess of Gemworld (7 episodes)

DC's World's Funnest (10 episodes)
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Green Arrow (3 episodes)
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Metal Men (5 episodes)
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Plastic Man (6 episodes)
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Shazam! (3 episodes)
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Super Best Friends Forever (5 episodes)
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Superman Toyko (2 episodes)
DC Database; DC Universe; IMDb; YouTube

Thunder and Lightning (2 episodes)
DC Database; DC Universe; IMDb; YouTube

Wonder Woman (3 episodes)
DC Database; DC Universe; IMDb; YouTube

...And there were plenty of other series of shorts, most of which I haven't seen, and probably wouldn't care much about. But I do intend to look for some of the ones I haven't seen yet.