When I bike out to Coney Island along Ocean Parkway, judging how close I'm getting by where I am in the alphabet of street names that starts at Avenue D and ends at Avenue X, I often wonder what happened to the missing letters. There's no A, B, or C, or for that matter, no E, F or G. (I must note, though, that except for E, each of these streets starts with the appropriate letter (Ablemarle, Beverly, Clarendon, Farragut, Glenwood)). And, in fact, both Farragut and Glenwood used to be the more simple Avenues F and G.
If you want to see other Brooklyn streets that used to be known by another name, check out Steve Morse's list, which compiled by poring over old maps and city directories.
Some streets haven't just changed names - they've disappeared altogether. For those, the master is Kevin at Forgotten NY. Many of the Brooklyn streets that he catalogues were destroyed by construction of the Brooklyn Bridge, Cadman Plaza, city and government buildings, or by Robert Moses' construction of the BQE.