Fushigi Yuugi, Tate no Yuusha no Nariagari Recommendations
Both start with the main characters being drawn into a book and ending up in another world in which they need to fulfill some kind of prophecy while not being the only one from another world. Main characters need to find companions on their journey. While it's about four different heroes in Rising of the Shield Hero, it's about four different nations with a priestress each in Fushigi Yuugi (although only two of them get some real meaning during the main series). Both series include lots of intrigues against the main characters.
Both series are isekai about a prophetic hero being transported to another world via a book found in a library and attempting to overcome a harrowing journey and adversity.
Both also have that appeal that pumps you up and makes you want to jump right into the next episode to root for the hero.
The only real difference between the 2 is the Fushigi Yugi is more of a Shoujo and Shield Hero more Shounen.