Here's a start: https://www.new-york-city-travel-tip...s-attractions/ And there's this: https://www.newyork.co.uk/events/wha...-january-2019/ A sport event would be great as well. Nearly the end of the NFL season, ice hockey etc.
This could also be interesting: Perhaps you can find better prices, but it gives you a nice list! https://www.getyourguide.co.uk/s/?q=...ork&et=515&p=1
New York has tons of highlights. Plan indoor activities for January, it can be very cold then. The museums are wonderful and sooooo big. Try to avoid schooldays... Tons of kids running around the building doing assignments. My wife and my youngest went during the Summer months and visited the Intrepid and landed in an 'Open Air Cinema' on deck or the carrier, showing Star Wars III (the first film)! Their highlight of the trip.
9/11 Memorial is a must, but get tickets in advance and be aware of the queues: security. Boat trip to Ellis Island is very impressive as well; search for ancestors who made the trip from The Old Country to NY before you go to Ellis Island can be very interesting! https://www.nps.gov/elis/learn/educa...rds-online.htm
Furthermore (according to my wife) January is the perfect month for shopping: like in Europe, sales are low in January (after Xmas) and shop owners want to attract people using sales and advertising.
Movies before you go: The Adjustment Bureau and New York, I love you.
Menno