[Sunred]

Quote:

Originally Posted by Future Rider Prism

Okay, great! I'll keep those in mind when I get around to starting the series. Thanks!

Like Kurona and Switchblade said, X and Max are good places to start, and since 2021 is also the 25th anniversary of the 1996 show Ultraman Tiga plus there is a high possibility the new 55th anniversary show this year is likely to pay tribute to it based on rumors, Ultraman Tiga would be another show worth checking out following these two. Ultraman Tiga is symbolic in that it is the 30th anniversary show but also the show that brought back the franchise after its hiatus following the end of Ultraman 80. And it is the first to introduce form changes, giving Tiga the ability to switch into three modes of combat including his default mode, thus giving him the name Tiga(pronounced Tee-gah) the Indonesian word for the number 3.
Personally though these shows I would like to say are recommendations if you prefer to start with something more modern yet have the most elements of a classic Ultraman show. After giving one of the previous recommendations a watch definitely give the original 1966 Ultraman a try.