Adventure stories are also common. They could go on quests together in the Underground. Papyrus's eagerness for heroic deeds combined with Chara's knowledge and skills (depending on how they are portrayed) could lead to some exciting adventures filled with challenges and the discovery of new places within the Undertale world.
Redemption is another theme. Chara is often seen as a more morally ambiguous character, and fanfictions might explore how Papyrus could influence Chara towards redemption. Papyrus's strong sense of right and wrong could play a big role in this kind of story.
One common theme is the exploration of an unlikely relationship. Since Papyrus is a very positive and friendly character and Chara has a more complex and somewhat controversial backstory in the Undertale universe, seeing how they interact and form a relationship is often explored. For example, some fanfictions might focus on Papyrus helping Chara to overcome their past traumas.
Another theme could be adventure - related. Since they are both characters from the game Undertale which has an adventure - based storyline. They might go on adventures together in the fanfiction, facing challenges and growing closer as a result. Maybe they team up to save the Underground from a new threat or something similar.
I really liked 'The Unlikely Bond'. In this fanfic, Papyrus and Chara start off as enemies but gradually come to understand each other. The story has a lot of emotional depth, with Papyrus trying to see the good in Chara and Chara learning to open up. It's full of heartwarming moments and some really cool plot twists that keep you hooked.
One common theme is friendship. Papyrus and Undyne are often shown building a strong bond of friendship through various adventures or just daily interactions in the Underground. Another theme is mutual respect. They both recognize each other's strengths, like Papyrus admires Undyne's fighting skills and Undyne respects Papyrus's determination.
One common theme is the exploration of their relationship in the Underlust AU context. Since it's an AU with a focus on different interpretations of the characters' personalities and relationships, fanfictions often delve into how Papyrus and Sans interact with each other romantically or platonically in this altered world.
You might also check out Tumblr. There are a lot of Undertale fans on Tumblr who might share or write Papyrus x Chara fanfiction. You can search relevant tags such as #PapyrusxChara or #PapyrusCharaFanfiction. Just be aware that Tumblr's search isn't always as accurate as the dedicated fanfiction sites, but it can be a good source for finding unique and creative works.
Common themes in 'yandere chara x sans fanfiction' include possessiveness, which is a hallmark of the yandere character. Another is the idea of a relationship that is not based on healthy mutual understanding but rather on Chara's one - sided and extreme feelings. There's also often the theme of the 'other' or the outsider. Since Chara is acting in an abnormal way, Sans and those around him might see Chara as an 'other', which can create a lot of tension in the story.
One common theme is friendship. Their bond is often explored, like how they support and care for each other. For example, in many fanfictions, they are there for each other during tough times in the Underground.
A common theme is the power of friendship. Despite their differences, Chara and Sans can form a bond that helps them both grow. Another theme is the exploration of good and evil. Chara has a complex moral standing, and Sans is often seen as a more morally 'good' character. Their relationship can be used to question what is truly good or evil.
One common theme is friendship. It could explore how the two characters from different 'worlds' (as represented by their different character concepts) become friends and support each other.