That clip itself went meta in his review of Adventures of Sonic the Hedgehog, when he told people that he was sick of that joke and that we wouldn't hear it again. The joke itself then shoehorns itself into the clip, squashing the Critic in the process.
Also in his Godzilla review, when he mispronounces the main character's name, said character will appear in a clip and state his name, to which the Critic says "whatever". It's most ridiculous the last time, as the name the critic uses lasts for several seconds.
There's also the use of the "Wah Wah Wah Waaaaah" sound effect followed by him shrugging when a stupid line or action happens in the movie. If it happens multiple times in one review he shrugs higher every time.
In a Superman review, he uses this sound effect so much that the machine which makes it breaks.
In The Nostalgia Chick's Labyrinth review, she pointed out a running gag by having the word "Gag" with stick-figure legs run across the bottom of the clip. Yes, it's a running gag based on running gags themselves.
Whenever a delicate subject comes up (usually an actor who can't be made fun of comfortably due to tragedy striking them since the thing being reviewed was made), the issue is forcibly brought to The Critic's attention by The Elephant In The Room. As in, an actual elephant in the Nostalgia Critic's room who just hangs out and demands to be acknowledged when awkward jokes happen or tempt.
Recently, the involvement of Mara Wilson, on or off-camera, as a special guest, in a cameo, or as a co-writer in various Doug Walker / Lindsay Ellis projects and reviews is becoming this, due to her friendship with both of them. She may or mat not be demon-possessed and seeking REVENGE!!! in a lot of the on-camera appearances. Slightly averted as she doesn't want to wear out her welcome, but she does show up frequently.
Since Doug started watching Avatar: The Last Airbender , he's incorporated not one, but two running gags - when someone crashes off-screen, the Cabbage Guy will shout "MY CABBAGES!!" and he'll also use the foaming mouth guy clip to sarcastically respond to elements in the subject of his reviews that are built up to be more awesome than they really are.
Perhaps more a tradition as it's done annually, but every January for Nostalgia Critic has some sort of theme in the reviews (For instance, 2014's "Nicolas Cage Month") and he always kicks them off as such: