I've seen and enjoyed some too, like Hidarimari Sketch – a story about cute girls doing cute things together in an art school – and they, like Hidarimari Sketch, don't all lean toward being suggestive ...
As someone who loves gacha games - and I've played some of the best out there - this has to be a top pick in my book. If you're new to the game, don't worry, everything will make sense in due time.