My biggest recommendation would be Transit Girls for a romantic relationship between women! I thought it was super cute. Yes or No might also interest you.
In between, I'll add one that's sort of odd: Last Friends. There is a big focus on the friendships in this, as well as lots of implying that Ueno Juri's character is in love with her best friend (although it is also suggested that the character has gender dysphoria, so it's trickier to categorize)
As for non-romantic relationships between women, the first one to come to mind is Ghost Writer, the relationship between the two main characters (a famous writer and her ghostwriter) is so intriguing and complex; I enjoyed it immensely.
Some other recs, although I did not enjoy them nearly as much as Ghost Writer, are Seigi no Mikata, which focuses on the relationship between two sister, and Underwear, which although is more focused on the work aspects also features a heavy dose of the main character's relationship and understanding of her boss.
Also some dramas I plan to watch that appear to be heavily focused on women and I've heard great things about: Age of Youth and Ode to Joy
