Here are some app recommendations from me. All the links are for the Google Playstore, sorry for no Apple AppStore links, but you can just look up by names.
Best traveling app for any country; gets you everything from public transport to cycling and walking directions.
Best offline maps app, has cycling directions also.
Official SL app, you can buy tickets on this app as well.
This is my favorite because I can have my frequent routes saved here to have quick access.
A map of the Stockholm metro with live status of each station (bus and metro both)
One of the best services to travel around Europe. Probably the cheapest way to go to Copenhagen.
Accommodations for traveling.
Transfer money by phone (You need a Swedish bank account)
A lot of uses for this, for verifying your identity. (You need a Swedish bank account)
The tax agency, if you work here, this is handy for filing tax returns and a lot more things.
Track your monthly budget and expenses.
Track the weekly offers at ICA supermarket.
Track the weekly offers at Lidl
I recommend buying Skype credits for making voip calls, I use this to call to India and it’s quite cheap (~ INR 1/min)
The best way to socialize with locals with similar interests.
I find this for taking class notes. Notes can be organized in notebooks.
Another Competitor of One note, I usually use this for travel notes.
Great note taking and checklists app.
This is a great meeting planner app.
A better version of Google Calendar with an attractive UI, you’ll need calendar a lot, all the classes can be tracked on it.
Another great To-Do lists app
Great way to learn a new language.
A perfect way to improve vocabulary in any language.
This is very handy, there are at least 3-4 chances every year to see Aurora Borealis in Stockholm.
One of the best scientific calculator apps out there.
Who want’s to pay for a Gym trainer.
Don’t be surprised, This is in-fact one of the most useful apps.
Very handy to decide how many jackets should you be carrying.
The most important app, this is the proof of you being a student in Stockholm, will need to show the Mecenat card or the app when tickets are checked in the metro, avails a lot of student discounts as well.
Last but not the least, keep the music playing.