The is an alternate hypothetical where tanjiro is a descendant of Yorichii

Tanjiro comes home to find his entire family dead. He was later found by Giyuu and was sent to Urodaki to train to become a demon slayer. But after he got their he got dreams of someone with hanafuda earrings(Yorrichi) performing a breathing technique he heard him call sun breathing that looked very similar to his family dance. After he told Urodaki about this he immediately told Tanjiro about sun breathing and that only one person was able to do it. After seeing that Tanjiro cam actually use sun breathing he immediately told him to train and train more in this breathing technique. Over the next two years Tanjiro would get the same dreams and has learned how to perform the 12 moves flawlessly and is still training to do the 13 form. Read the first chapter for more information.

what if tanjiro kamado was born with yoriichi's potential? read the story to find out. some stuff is changed but some is canon

Just another Rimuru's Time travel story Rimuru didn't have a chance to go back on his current timeline so he think that the only solution is to go back in the time when he was got reincarnated as a slime.

A Tensura what if of the Silver Primordial. Rimuru was brought into the past by Raphael, the ultimate skill made sure to give him a powerful new vessel to inhabit. Follow Rimuru as he cause anomalies and create new enemies due to the alteration of the timeline. 'Master, I am sorry this is the only way for you to survive. I won't let you die because of my incompetence once more.' 'Raphael stop! Don't do it! You're killing them all! Stop I don't want this! I can't live knowing that I survive because of their sacrifices stop!!!' 'Master, I'm sorry this is for the best even if it's an order, my priority is your safety.' All Tensura characters and settings are from Fuse, the author. The ships are Rimuru: Velgrynd Luminous Chloe