One common theme is the exploration of innocence. When Merlin is de - aged, he often regains a sense of childlike wonder and innocence. This is contrasted with his usual more jaded self as an adult in the show. For example, his reactions to magic might be more pure and unrestrained.
There's also a series where Merlin is de - aged due to a spell gone wrong. In this fanfiction, we see a more innocent and yet still powerful Merlin. It delves into how the characters around him, like Gaius, have to take on different roles to protect and guide this younger Merlin. It's quite interesting as it shows a different side of the well - known characters. The story also focuses on how Merlin's de - aged state affects the political situation in Camelot, as his presence and powers are always a significant factor in the kingdom's affairs.
One popular 'de aged merlin fanfiction' is 'The Young Merlin's Adventures'. It shows Merlin as a child in Camelot and how his magic still manages to get him into all sorts of interesting situations. Another is 'Merlin: De - Aged and Discovering'. This one focuses on how the de - aged Merlin rediscovers his relationship with Arthur in a new light.
Fanfiction.net is also a good place to look. Just type 'de aged merlin' in the search box and it will show you relevant fanfictions. However, the quality may vary, so you might need to read a few to find the really good ones. Some writers also post their 'de aged merlin fanfiction' on their personal blogs or Tumblr pages, but it can be a bit harder to find them that way.
One common theme is the change in Draco's personality. When he's de aged, he might be more innocent and less influenced by his family's dark views. This can lead to new relationships and interactions with other characters, especially Harry and his friends.
One common theme is self - discovery. When Hermione is de - aged, she often has to re - evaluate who she is without all her previous experiences weighing her down. Another theme is the rediscovery of friendship. Her friends see her in a new light and she has to re - establish those bonds.
In some fanfictions where Batman is de - aged, it could lead to really interesting storylines. For example, he might have to rely on his younger self's instincts more. He could be more impulsive in a way, which would be a big change from his usual calculating self. Also, his relationships within the Justice League would shift. His friends might see him as more vulnerable or in need of protection, which he would probably resist.
Well, without having read the actual 't challa gets de aged fanfiction', it's hard to say precisely. However, based on the title, it might involve T Challa, perhaps from the Marvel universe if we assume it's related to that. The 'gets de aged' part implies that something causes T Challa to become younger, and the fanfiction would then explore the consequences of this. Maybe it's a time - travel - related incident, or a magical spell. There could be a whole new set of adventures and character developments as a result of this de - aging. For example, he might have to deal with not being recognized by his friends or having to adapt to a younger body's capabilities.
Redemption is often a theme too. The de - aged Draco can be seen as a chance for him to start over, to be different from the somewhat villainous character he was before. This ties in with the relationship with Harry, as Harry might be more open to this new, younger Draco. It also gives the author a chance to rewrite some of the negative aspects of Draco's character arc in a more positive light.
You can try fanfiction.net. It has a large collection of various fanfictions, including those related to a de - aged Batman. Just use the search bar and type in 'de aged batman' and you'll get a list of relevant stories.