I really don't use anything regularly besides Instagram, Uber, Citymapper, and Spotify. I'm boring like that. I prefer to do most things on a computer. A lot of apps frustrate me with bad UI. I only use things that I consider a "necessity".
My most used apps are Instagram, Alien Blue, eBay, SNKRS, Masterpiece and Grailed.
Instagram is for all my photography, meeting new people and models as well as buying and selling gear.
Alien Blue is my Reddit app where I get all my news and post about photography related topics.
eBay is where I spend a lot of time researching new cameras.
SNKRS takes a spot as I check it to keep up with the latest street wear trends.
Grailed is pretty much the same reason as above.
Masterpiece is how I kill time on the Subway.
The obvious answer would be Instagram - I love double-tapping on other people's content and see what's trending. I also use Houseparty to video chat multiple people at the same time. Also, I love Spotify because their music selection is the best and their playlists are better than some of their competitors.
Instagram is probably my most used app. Scrolling through my feed is the perfect way to stay updated on all of the great things my friends and family are doing. Spotify is also a necessity. I probably have over 30 playlists for every occasion. Venmo has been a lifesaver throughout my college experience and I don't know where I would be without my GIF Keyboard.
One of my new favorite apps is ClassPass. I just joined a few months ago and it's been a great and economical way to try a variety of classes across the city without joining a gym. I'm also a big fan of the app Seated, a restaurant reservation app similar to Open Table. The app allows you to make reservations and when you upload your bill after your meal, you receive $10 - $50 reward credits for Lyft, Amazon, or Starbucks. Also another food app (because I love food and trying new restaurants) I use often is Tab. Whenever I go out to eat with friends, we use the app because you are able to upload a picture of your bill, select the items you had, and it splits the tab with tax and tip. Super convenient when eating out with big group