Re:Zero kara Hajimeru Isekai Seikatsu, Youjo Senki Recommendations
Although these anime are different as a genre, one is about fantasy world, another is about XX century world. HOWEVER! Both have same concept idea, and that MC was sent to another world via time travel by someone who is superior (P.S. this isn't a spoiler as long as you watch 1st episode of both). It is interesting to mention that even opening of Youjo Senki is also very similar to Re:Zero kara Hajimeru Issekai one.