Atlus has revealed a logo to celebrate the 30th Anniversary of the Shin Megami Tensei series, with the first title, Shin Megami Tensei, releasing in Japan on October 30, 1992.
There are both English and Japanese versions of the logo.
English
Japanese
25th Anniversary
The 25th Anniversary took place in 2017, and saw various merchandise and events, including two concerts, the release of Shin Megami Tensei: Strange Journey Redux, and the first teaser for Shin Megami Tensei V.