It's pretty easy to get around in Stockholm. SL (Stockholm Public Transport) runs a full system of public busses, subways, trams, and trains. It's relatively efficient, and usually on-time. There's also more than enough bitumen to go around every person who owns their own car as well.
HOWEVER! Stockholm (And Sweden in general) have some other pretty interesting methods of mass transit:
The city of Stockholm is built on an archipelago.
There are many private jetties and boats, with a lot of Stockholm culture and pasttime based on access to the Baltic ocean water that flows through the area. SL maintains a fleet of ferries that are available as public transit, making stops through various places throughout the city. The larger ports are Slussen, Nybroviken, Djurgården, and Hammarby Sjöstad.
The ferries are linked into the same public transit system as all the regular land-based vehicles, so your transit card from the local Pressbyrån will work on both busses AND boats!
Just a small thing of interest, in the middle of the city there's a boat that's just sunk into a narrow canal. It looks like it's been there a while!
Stockholm city is a very walkable, and very ridable city. With wide walkways, and plentiful bike lanes, grabbing one of the publically available bikes for hire is fast and convenient. Most cities have this form of transit, but it's worth mentioning. Nothing mind blowing here...
This one blew my mind, as a newcomer from a small "city" in Far North Australia. On nearly every curb, outside every supermarket and newsagent, and every place where people gather, are a pile of these scooters from various different companies...
Also there are so many Teslas...
Until next time!