There are the charitable organizations as well as the corporations, of course. The Salvation Army on 9/11/01 was almost immediately at work once we were attacked—no one had to ask them to be there, this is what they do, no government mandates or bureacratic holdups. This is from a piece I did a while back on

Within 45 minutes of the September 11
terrorist attacks, about 200 Salvation Army
officers got themselves to the crash sites in
New York City, Virginia, and Pennsylvania,
assisted by some 5,000 volunteers. (No one
even had to ask, they just marched to the
scene, ready for whatever they faced.) According
to Salvation Army reports, personnel
got to what would become known as
“Ground Zero” in Manhattan so quickly that
one of their trucks was covered in debris
when the first tower of the World Trade
Center collapsed.
The Army quickly set up 21 mobile feeding
stations in Manhattan that served 300,000
meals during the first 72 hours after the attack.
As Worth magazine reported, they provided
whatever was needed, literally: “American
flags to drape over a refrigerated truck
bearing the remains of a fallen policeman,
hundreds of teddy bears to comfort the children
of the victims, Vicks VapoRub for the
rescuers to smear inside their nostrils to
cover the acrid stench of death and burning
metal. Small things, but, as the grateful recipients
declared over and over, they made all the
difference at ground zero.” Salvation Army
staff and volunteers gave rescue and recovery
workers foot massages. (“We would take
their boots off, and they would literally be
melting,” an Army soldier reported. “We
would massage their feet, put on salve, then
put on new socks and boots.”) They seemingly
thought of everything and everyone,
from all reports: Salvationists even handed
out phone cards for the rescue and recovery
workers to call home with. Coordinating with
federal and city workers, the Salvation Army’s
counseling experience made them lifesavers
not only for grieving families, but for workers
faced with the overwhelming death and destruction.
From around the world donations have
come in, and the Army has used whatever
they have been sent. Gloves, respirators,
hardhats, bottled water. Children have sent
in snack packs with notes for the rescue
workers. One typical letter, this one from a
child in Alabama, reads: “Dear Volunteirs[sic],
Thank you for helping. It seems you are
helping all of America.”