You could do worse than the English translations by Laura Gibbs (2002), published by Oxford University Press and available online at Gibbs’ site ‘Aesopica’.
The two fables you asked about are Perry 579 (= Gibbs 597):
A traveller was walking along and found a sword lying in the road. He said to the sword, ‘Who lost you?’ The weapon replied, ‘One man has lost me, but I have caused the loss of many a man!’
‘The Man and the Sword’. Translated by Laura Gibbs (2002). Oxford University Press.
and Perry 621 (= Gibbs 89):
The peacock was a remarkable bird both because of the beauty of his feathers with their various colours and also because he was gentle and courteous. On his way to the assembly of the birds, the peacock ran into the raven. The raven asked the peacock if he would give him two of his feathers. The peacock said, ‘What will you do for me in return?’ The raven replied, ‘I will squawk your praises throughout the courts in the presence of all the other birds!’ So the peacock gave the raven two of his feathers. The crow then made the same request of the peacock and obtained two of the peacock’s feathers, as did the cuckoo and all kinds of other birds, until finally the peacock was plucked completely bare. The peacock was supposed to nourish and protect his chicks but he was unable to do so since he didn’t have any feathers. Winter came, and he died. His chicks went away and lived as best as they could on their own.
‘The Birds, the Peacock and his Feathers’. Translated by Laura Gibbs (2002). Oxford University Press.
Gibbs’ translation includes 600 fables, so some fables from Perry’s list are not covered, but then Perry’s list doesn’t cover all the Aesopian fables either. See the Aesopus website for hundreds more in Latin.