Totsukuni no Shoujo (2022)

Both have similar atmospheres and similar vibes. Girl on the Other Side is a tad more cutesy and iyashikei while Angel's Egg is a bit more psychological. Both have stunning and unique art styles and tell a more subtle and esoteric kind of story. If you like one you'll like the other, though keep in mind sacrificing the cutesy side for a more dramatic one and vice versa. (Also if you liked Over the Garden Wall check out either of these) 

The story of both starts from nothing and takes you nowhere, in addition to not concluding anything, not explaining anything, not telling anything. They are visually similar. And both are very bad. If you hated one, you will also hate the other, because neither of these two anime is any good. 

1. Big monster adapts an abandoned little girl 2. Little girl is an adorable child 3. Traveling in a fantasy world Humanoid monster is seen fostering a girl while traveling to search for the last human civilization to save her. Both shows depicts that even a monster can become a father-figure to a child without any relationship or ill-intention.