Lucy could be an interesting choice too. She's more of a magic user who relies on her celestial spirits. Wolverine might be initially confused by her magic but then come to see the value in it. Their interactions could be humorous as she tries to explain the intricacies of her magic to him, and he tries to teach her some hand - to - hand combat skills.
Definitely Gray. Their personalities are quite different. Gray is cool - headed and uses ice magic, while Wolverine is more of a rough - and - tumble fighter. The contrast in their powers and attitudes would lead to some great banter and interesting team - up moments.
Maybe Wolverine's healing factor becomes a mystery in the Fairy Tail universe. The guild members could be both intrigued and a bit scared of it. He could then use his skills to train the younger members in combat while also trying to find a way back to his own world. This would create a lot of character interaction and development opportunities.
Natsu would be a likely candidate. He's always up for a challenge and not afraid to take on powerful opponents. He'd probably be the first to rush towards Godzilla, either to fight it or try to befriend it in his own Natsu - like way.
Bardock would probably be initially cautious around the Fairy Tail characters. Given his Saiyan nature, he is used to a more cut - throat and survival - based environment. But as he gets to know them, he would start to respect their loyalty and sense of family. For example, he might be impressed by how the guild members always have each other's backs, much like how Saiyans rely on their comrades in battle.
Definitely Naruto and Natsu. Their personalities are quite similar in some ways, both being hot - headed and determined. In a fanfiction, their interactions could be really fun to read. They might start off as rivals, constantly trying to outdo each other in terms of strength and courage, but then gradually become friends and learn from each other's skills.
Yugi and Natsu would be an interesting pairing. Yugi is calm and strategic, while Natsu is impulsive and powerful. They could balance each other out. Yugi could use his intelligence to plan their adventures, while Natsu could use his fire - based magic to fight off enemies. Another interesting pair could be Erza and Kaiba. Erza is a strong and disciplined warrior, and Kaiba is a proud and powerful Duelist. They could have some epic battles of wills and skills.
Erza and Captain America would be an amazing combination. Erza is a strong and disciplined warrior in Fairy Tail, and Captain America is the symbol of justice and leadership in the Avengers. Erza's various armors and combat skills combined with Captain America's shield and strategic thinking would make them a formidable team. They could lead the combined forces of Fairy Tail and the Avengers in battles against powerful foes, and also inspire the other characters with their unwavering determination.
Spiderman and Erza would make for a strong pairing. Erza is a very powerful and disciplined mage. Spiderman could be in awe of her combat skills and leadership. They could fight side - side against powerful enemies, with Spiderman using his webs and agility and Erza with her various armors and weapons.
I think Kakashi and Gray would have some cool interactions. Gray's ice - magic and Kakashi's fire - based attacks (like Fireball Jutsu) could lead to some interesting battles or training sessions. Also, Kakashi and Lucy could be fun. Lucy's celestial spirit magic and Kakashi's summoning jutsu could be compared and contrasted. And of course, Kakashi and Makarov. The old and wise guild master could give Kakashi some unique insights about the Fairy Tail world, and Kakashi could share his ninja wisdom with Makarov.
Mirajane would be an interesting character to interact with. She has a very mysterious side to her, with her Satan Soul ability. The fan in Lucy's body could try to uncover more about her past and the secrets of her powers. And Mirajane is also very kind and motherly towards the guild members, so the interaction could be very warm and friendly.
Another character who could run a burger joint is Macao. He seems like the type who would enjoy the hustle and bustle of running a business. He has a lot of experience in the guild and is good at dealing with people. He could use his fire magic to cook the burgers in a unique and fast way, adding a special touch to the food at his burger joint.