OK, then, a few more of the Indian States to cross off the list. First, Bamra State

CTO and favour-cancelled material isn't hard to find from Bamra, but actual commercial mail is another matter. The State Post Office only ran from 1888 to 1895.
Then, something rather special from Barwani State:

an imperf between pair of the 1922 2 Anna on thick glazed paper, and in case that was rather strong meat for some

the two 1940 animal definitives of Bhopal. Bhopal probably intended these to be the start of a longer set, but the Second World War got in the way, and the State never did finish the set.
And to round off India, another special cover, from Dhar State:

The typeset ½ Pice and 2 Anna - Dhar stamps were only valid between 1897 and 1901.
And finally, Las Bela State. For its ten year life (1897-1907), it was in British India, but these days it falls under Pakistan:

the 1899 ½ Anna on greenish-grey granite paper