I've noticed this too both in those around me and myself (mid 20s). I don't identify as queer and have always been "straight", but more recently the thought of sucking a trans girl's dick is kinda hot? I'm not attracted to guys at all, so it would have to be someone who is otherwise extremely feminine, but eh?

I don't know what to call it and I honestly don't really care to think about or try to label it because it's a worthless distinction. It helps that most of my friends are queer so I've had any and all stereotypes/expectations surrounding attraction completely shattered, and I've found this to be true of more people I meet over time who don't identify with queer culture at all. I'll be interested to see how this continues to change in the next 20 years.