Another great plotline could be that Harry is somehow transported into the Autobots' universe. He has to find a way to get back home while also getting involved in their internal politics and power struggles. The Autobots might be divided on whether to help him or not, and Harry has to use his wits and charm, as well as his magic, to convince them to assist him in his journey back to the wizarding world.
Perhaps in the 'harry an autobot fanfic', there is a plotline where Harry has to learn about the Autobots' culture and technology. He might start off not understanding them at all, but as he spends time with them, he discovers new ways to use his magic that he never thought of before. This could lead to some really cool adventures and battles where his newfound knowledge is put to the test.
Well, one possible interesting plotline could be Harry teaming up with the Autobots to fight a common enemy. Maybe there's a powerful Decepticon that threatens both the wizarding world and the Autobots' home planet, and Harry's magic combined with the Autobots' technology is the key to victory.
There might also be other Autobots such as Bumblebee. Bumblebee could be Harry's friend, always there to help him out in tight situations. Maybe there's a human - Autobot liaison character who helps Harry understand the Autobots better. And let's not forget, there could be some antagonists from either the wizarding world or the Decepticons' side who play important roles in driving the story forward.
One interesting plotline could be Harry's adventures in the afterlife realm where he has to deal with different types of souls. Maybe he meets some souls with unfinished business and tries to help them move on.
Another plotline might involve Harry forming unique alliances with other druids. They could work together to protect an ancient druidic site from dark wizards who want to use its power for evil. This would lead to some exciting battles and magical duels.
Perhaps it focuses on his reasons for becoming a thief. It could be that he was forced into it by some difficult circumstances in his life. Like he was wrongly accused of something and had no way to prove his innocence, so he turned to stealing to survive and seek revenge.
One interesting plotline could be Harry's journey to master new paladin skills. For example, he might have to overcome challenges in a magical forest to find a rare weapon or spell that enhances his paladin abilities.
In 'harry is a king fanfic', a possible plotline is Harry having to deal with a rebellion. He would need to use his wits and leadership skills to quell it. Also, his love life might be intertwined with his role as king, like falling in love with a princess from another land which could have political implications.
One idea could be to focus on a new Autobot character arriving at Autobot City just before the battle. This character could bring a unique skill or weapon that helps turn the tide of the battle in unexpected ways.
Perhaps a plotline where Harry discovers a long - lost Templar secret that has the potential to change the balance of power in their world. This could lead to him being both a target and a key figure in a great struggle within the Templar order.
One interesting plotline could be Harry learning elven magic. Since Elrond is an elf, he would have different knowledge of magic compared to what Harry is used to in the wizarding world. Another could be Harry's interactions with other elven characters. He might form unique friendships or rivalries. Also, his growth in a completely different cultural setting than Hogwarts would be fascinating.
One interesting plotline could be Snape initially struggling with his new role as Harry's guardian. He's used to disliking Harry, but as he gets to know him better, he discovers Harry's hidden talents and insecurities. For example, Harry might show an aptitude for potions that Snape had never expected, and Snape has to learn to be a positive influence in Harry's life instead of a critical one.