 If you liked
Campione! Matsurowanu Kamigami to Kamigoroshi no Maou
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 ...then you might like
Seiken Tsukai no World Break
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similarities:
-both of the mc use words of power to defeat the enemy
-harem, every episode the mc meet a new girl
There's quite a lot of similar elements, but the main one is each certain group or country having one extremely OP dude out of a small number in the world, which includes the Protagonist being the OP guy for Japan, making him a well-known character in each anime.
However, in Seiken Tsukai, characters have powers from a past life, whilst in Campione, characters assume the powers of characters from mythology.
Both animes have Supernatural, School, Romance, and Harem, too.