I can't think of any popular famous quotes along those lines. But it's quite common to say things like:
Not everything is so black & white.
Rainbow colours are also used to represent this, especially in sociopolitical organisations.
In times like this, where there is a lack of wise idioms in English, I would probably refer to Laozi. For example the start of chapter 41 is a perfect quote for this instance, to share with my English speaking friends, not just to highlight how everyone is different, but also to affirm how it's a necessary thing.
上士聞道, 勤而行之.
中士聞道, 若存若亡.
下士聞道, 大笑之.
不笑不足以為道.