BB10 is definitely my favourite, and it has a black girl goddess called Libra
The cast is quite diverse and there's like an 80 year old on it too.
If you want the most dramatic season, then I'd say watch BB12 or BB13 for Rachel Reilly <3
Most people say BB6 is the best though, with Janelle in it. It's kinda like BB13UK with insiders vs outsiders. So that might be a good starting point for you, or BB10. Both are amazing. BB3 is good but is more simple than the others, but it has my favourite player of all time in it.