Hi,
I'm old fashioned and so, as the M5 was sold from 1971 to1975 or 76 I'll suggest a Summicron from that period. And I'd make the same suggestion for the 35, 90 and 135mm lenses.
OTOH, the Jupiter-8 is a pleasant f/2 lens and the Industars are good also but f/2.8 at maximum but you can sometimes pick them up for pennies...
It really depends on how much you want to spend and a bit of luck with the previous owner. Alas, lenses are easily dropped and there are idiots about who are good at taking them to pieces and not so good at the re-assembly part.
So assume you'll have to test the lens carefully with a roll of film and, perhaps, get it checked and sorted out by an expert. Or go to a dealer who is prepared to guarantee everything.
Anyway, have fun.
Regards, David