BNA: Brand New Animal: The closing credits of the first five episodes show Michiru's best friend Nazuna in human form.
While not exactly credits, the opening of the Fullbring arc of the anime changed as Ichigo's Fullbring evolved.
The same thing was done before with Houkiboshi, which gives the spotlight to one of the captains and their lieutenant (and sometimes, other members of that Gotei 13) each episode that ending theme was used.
The Bleach ending theme Haruka Kanata gives the spotlight to a different character every episode.
After the Reincarnation Arc, which resolves the story of the first Wizard King, the narration changes to talk about Asta and his desire to become the Wizard King. After his name is revealed and the fight is shown in detail, the narration changes to mention his name and show more in-depth visuals of the battle.
Black Clover has the Opening Narration talk about how the first Wizard King became a legend for defeating a demon and saving the kingdom.
Best Student Council uses the "simple" revealing-silhouettes version.
Bakuon!!, similarly to the K-On example below, strategically inserts Chisame into the opening sequence following her introduction midway through the season.
Most notable with the latter, with involves all of the important characters running through a field, with more appearing in subsequent episodes.
In Back Arrow, both the opening and the ending add characters to them as they appear in the show.
This seems to be an error, however, since the Blu-ray releases of every episode include the later version.
By Episode 4, the emblem is now shown with duller and darker colors.
During the Opening song in the first episode of Attack on Titan, The Emblem of Wall Maria is shown with bright, clear colors.
The second OP of Season 2 (Episode 15 onwards) changes to show how many days the class has left to kill Koro-sensei.
Following the God of Death arc, the opening of Season 2 Episode 9 shows Irina after her Good Costume Switch, and the God of Death's maskless face.
Itona appears in the Season 2 opening from Episode 4 onwards, after losing his tentacles and joining Terasaka's gang in the previous episode.
Episode 18 overhauls the second OP's sequence with new images and animations of the characters in their summer uniforms as well as dancing on the beach in casual summer wear, highlighting the start of the summer break portion of the series.
The OP for that episode and the episode after that are sung by the voice actors of those six students instead of the ones who usually sing the theme tune.
Episode 7 follows six students in a group during a field trip to Kyoto.
Irina and Ritsu appear in the first OP after their introduction in Episodes 4 and 9, respectively.
Assassination Classroom: With the opening theme.
Both the opening and ending of the final episode credits include ALL of the characters, even those who moved on very early in the series. Like the ending credits, characters are added or subtracted from the opening as they are introduced to the cast, or they move on.
The ending credits evolve with changes in the cast or relations among the characters, such as the removal of characters who move on, or a character who was revealed in that episode to be buff going shirtless in the credits.
After she wakes up in Episode 7, the shot is changed to show her waking up, followed by the now-empty stasis tank.
The end credits of Aldnoah.Zero Season 2 end with a shot of Princess Asseylum lying comatose in a suspended animation tank.
Akuma no Riddle has a completely different ending for every episode, each corresponding to one of the students of class Black.