Plenty it seems, although I can't find any pre-modern black nobility. James Dalrymple, son of the Sir William Dalrymple, 3rd Baronet of Cousland, was a Lieutenant Colonel in India and married Mooti Begum and had children while there[1]. It was unlikely to have been all that uncommon.

And more recently, Emma McQuiston, the black daughter of a Nigerian, married the Viscount Weymouth, son of the 7th Marquess of Bath[2].

There is also Baron Sinha, a hereditary peerage created for an Indian, Satyendra Prasanno Sinha in 1919[3]. We're now on the 6th Baron Sinha.

[1] http://thepeerage.com/p3465.htm#i34641 [2] http://www.thepeerage.com/p1903.htm#i19023 [3] https://www.thegazette.co.uk/London/issue/31196/page/2612