First, some tips about Swedish adverbs. The original link is here.
There are basically three kinds of Swedish adverbs: plain adverbs, older noun or adjective case forms (mostly datives) surviving as adverbs, and neuter adjectives used as adverbs. The latter group is straightforwardly formed just as when one would form an indefinite neuter singular adjective, so there isn't much more to say about them.
Some basic adverbs are: igen (again), tillbaka (back in the sense of returning), fram(åt) (at/in the front, forward), bak(åt) (at/in the back, backward), in (inwards, inside).
Some prepositions can double as adverbs, sometimes in a sense very similar to the prepositional meaning, and sometimes in a slightly different sense. Examples: på (on), av (preposition: of, from; adverb: off), ur (out of), från (preposition: from, adverb: a wide and vague sense of away, out of reach, ahead of, etc), i (preposition: in, adverb: into).
Some preposition+noun phrases have been contracted to adverbs, e.g. iväg (away), isär (apart in a sense of drifting apart), itu (apart, in the sense of cutting or breaking, especially into two parts). Some of these have become petrified and only exist in connection with a limited set of words, e.g. ihåg (originally i+håg, e.g. `in mind', `in intension') which now mainly occurs in connection with the verb komma (to come), as komma ihåg någonting (to remember something; the originally construction similar to the English expression of something "coming to mind").
Some older adverbs (and other words) have petrified, much like the preposition+noun phrases mentioned above, into idiomatic adverbs with only a vague meaning of their own. The most common of these are probably an, till and för. (Note that both till and för are perfectly alive as common prepositions, though, meaning `to' and 'for', while an is mostly dead as a separate word in Swedish, although it has survived in German.)
Various directional, locational and demonstrative words can be considered adverbs, too; e.g. här (here), hit (hither), där (there), dit (thither) .
Then some adverbs (related to time) for today:
aldrig: never
alltid: always
då: then
förr: before
i dag: today
i går: yesterday
i morgon: tomorrow
ibland: sometimes
i allmänhet: usually
nu: now
nuförtiden: nowadays
när: when
ofta: often
plötsligt: suddenly
samtidigt: at the same time
strax: soon
sällan: seldom
tidigt: early
tidigare: earlier
än så länge: thus far
ännu: still
äntligen: finally
