ones that met your precise criteria from 220 titles I have in two of my mdlists Yuukyuu no Gusha Asley no, Kenja no Susume (mc accidentally develops eternal youth and after 5000 years researching magic and stuff he goes outside and makes contact with civilization) Why Doesn't Anybody Remember My World? (manga description is better than what I could say) Helck (complete, not tagged romance and the romance is mostly shown through flashbacks towards the later half and at the end kinda) the hero creates a "family"(emotionless hero that just follows orders gets a dragon wife and adopts two daughters) Villager A wants to save the villainess no matter what! (isekai in which mc trains and gains strength to stop the capital where he lives from being destroyed and to save the "villainess" of the game) next life (guy loses his life, is reborn in a fantasy world with the character he used to play in a game and then meets a girl who is hiding from the government and decides to help her)