Trigger's show for the current season. It's an anime original, so there's no way to tell if it will have a real yuri end or not. But so far the whole series has focused on the relationship between the two female leads who have shown no romantic interest in the MC. Interviews from various magazine sources state that Akane's and Rikka's relationship is the key to the story, and that the anime will have more about them in the coming episodes. That said, it's still entirely possible it will have a last second straight ending, who knows.

The director wrote a yuri web novel about two of the background characters that show up in the series.
http://ncode.syosetu.com/n9623dz/
Someone wrote up detailed summaries of all the chapters.
https://pastebin.com/raw/gbrFh6Pk

Here's a google drive folder someone posted with pretty much all the relevent yuri fan art for the series.
https://drive.google.com/drive/folders/1AZDnTPJ0Sfhr_WxsmtMCxpLsRMm3mzTP