One common theme is redemption. When they travel through time, they often get a chance to right past wrongs, like Angel getting a chance to save someone he couldn't in his original timeline. Another theme is the exploration of their relationship. Time travel allows the story to show how their relationship could have developed differently in different time periods. Also, the theme of fate vs. free will is common. They might try to change things in the past, but are constantly faced with the question of whether it's possible or if they are just following a set fate.
One great Buffy and Angel time travel fanfiction is 'Time's Echo'. It takes the characters on a journey through different eras of the Buffyverse, exploring how their relationships change with the time shifts. Another one is 'A Temporal Twist'. It has an interesting plot where Buffy and Angel are sent back to key moments in their pasts and have to make different choices this time around. There's also 'Time Travel Trials' which focuses on the challenges they face while trying to fix the timeline.
One common theme is the struggle between their love and the obstacles they face. Since Angel is a vampire, there's always the issue of his vampire nature conflicting with their relationship. Another theme is the intense emotions. Their first time is often depicted as a very passionate and emotional moment, filled with years of pent - up feelings.
Angel can be a prominent character in Buffy time travel fanfiction. His long life and complex relationship with Buffy make for interesting storylines. He could be a part of Buffy's time - traveling journey, either as a helper or as someone who is also affected by the changes in time.
In many Buffy and Angel fanfictions where they have a baby, it often explores new dimensions of their relationship. It could show them dealing with the challenges of parenting while also facing the supernatural threats they are so used to. Maybe the baby has some unique powers that attract both good and bad forces, leading to a whole new set of adventures for Buffy and Angel.
A recurring theme is redemption. Spike, in particular, may use time travel as a chance to redeem himself in Buffy's eyes or for his past actions. Also, the theme of fate versus free will. Do they have the power to change their destinies through time travel, or are they bound by fate? This creates a lot of interesting conflict and drama in the fanfiction.
There's 'Spike's Time - Traveling Adventure'. In this fic, Spike gets thrown into various points in time, and Buffy has to follow to save him. It delves deep into their complex feelings for each other. The descriptions of the different time periods are quite vivid, making it a fun read. It also shows how their relationship evolves due to the time - traveling situations they face.
One interesting Buffy time travel fanfiction could be where Buffy travels back to the day she was called as a slayer and tries to change some small events that she thinks might have a big impact on her future battles. For example, she might try to give herself some extra slayer training tips early on.
Another theme is self - discovery. Through time travel, both Buffy and Spike get to see different versions of themselves. They might encounter their past or future selves and learn things about who they are and who they could be. This helps them grow as characters and also affects their relationship. For instance, Buffy might learn from a future version of herself how to better handle her relationship with Spike, and Spike could discover a part of himself that was buried in his past that makes him more worthy of Buffy's love.
If Buffy decides to tell Angel, their relationship could become more complicated. Angel might feel a sense of responsibility but also be scared. He could be hesitant about getting involved due to his vampire nature.