I remember as a kid our yearly calendar usually came from a local business, just as some still do today. I remember one that had a little thermometer embedded down one side. One way a company would advertise was to print a calendar or diary, or to send seasonal greetings to their customers.
Another way to advertise was to sponsor a convention or national meeting and have souvenir books printed for participants. These would typically have local advertising and information, plus names or sometimes photos of the company holding the convention.
Some companies tried to foster a sense of family with their employees by holding annual picnics. I had never been to a company picnic, but a company I once worked for in Quebec had a family day at a "cabane à sucre", or sugar shack, in the spring, and we had a great time. I did go to a church picnic a couple of times. My grandmother's church held their spring picnic on the island where we lived. There was lots of food, games and entertainment. My Grampa was up for participating in all the races and games with us.
Use keywords: souvenir, employees, greeting, and name of business if you know it. Also, don't forget company magazines.
The Grand Trunk Railway employees annual pic-nic to Campbellford, ON 1883
Souvenir guide book issued complimentary to the American Medical Association at its 46th annual meeting, Baltimore, 1895
Eighteenth anniversary complimentary souvenir, 1902-1920: to the delegates, Trades and Labor Congress of Canada, Windsor, ON 1920