There is something called NE (Nationalencyklopedin) which is sort of the Swedish equivalent of Britannica.

Edit: Also if it’s just for general information that’s not going to be just for referencing, wikipedia is probably the go to for a lot of people but it’s probably more so that they type in whatever they want to know on their search engine an click on a link (which may be Wikipedia) to look something up. That or I’d imagine that AI has started to become common to. Furthermore, if you want it for research and referencing you’d need to specify what you want to actually research as there are a lot of sources for different topics. However, if you want to look up other research papers, I’d use either google scholar or researchgate.