Drat, wrong button.
I can tell you that
between blocks 328,000 and 350,999,
block 334,261 with a hash of 000000000000000000002d414bb8f9175ba6c6563721e1ba2c1373c2bd94f29f appears to be the lowest
[...]
There's bound to be lower further up in the chain, though - it'll just take longer to find them as the ratio of such low hash blocks vs all block hashes becomes lower.
There's an existing thread on this:
For fun: the lowest block hash yet, so I'll just post an update there. fwiw, 334,261 was indeed the lowest.