There's a nice piece by Alyssa Rosenberg on 'unions mobilizing on behalf of Democratic candidates'. Here are some highlights.
NATCA (National Air Traffic Controllers Association), one of the smallest federal union, contributed $1.9 million to congressional candidates. 79% of that money (over $1.5 million) went to Democrats. $500,000 was also spent to support AFL-CIO's Working America program to build support and alliances with non-union workers, and $150,000 to help the Democratic National Committee's convention planning activities
PASS (Professional Aviation Safety Specialists) which represents Federal Aviation Administration and Defense Department technicians, made $207,500 in campaign contributions, with 91% going to Democrats
IFPTE (International Federation of Professional and Technical Engineers), which represents Defense workers, made $30,500 in contributions as of Oct. 19, sending 93% of that money to Democrats
AFGE (American Federation of Government Employees) donated $592,050 as of Oct. 19, with 96% going to Democrats
NTEU (National Treasury Employee Unions), which also represents TSA workers, made $306,100 in contributions as of Oct 19, sending 95% to Democrats
In addition to the donations and through the AFL-CIO's coordinated efforts, union members have also volunteered on campaigns -- such as making telephone calls, walking door-to-door and other various on-the-ground efforts to reach voters.