Alitalia has an offer for new account signups through March 30th.
You’ll receive 2000 miles just for signing up. (Miles post in April.)
You also receive 2000 miles for having your first account activity within three months of signup.
And 2000 more miles for flying Alitalia by April 30th. (Miles awarded the month following when they’re earned.)
I’ve flagged the strategic value of the Alitalia program in the past for some sweet spots in their award chart and the opportunity (uncommon among many non-North American programs) to use double miles for any seat. They are of course a US American Express Membership Rewards transfer partner.