Basically there are five big categories of role:
Investigative/Informational
The archetypal role here is Cop, aka Seer, who investigates a player at night and determines if they're mafia. All other investigative roles are essentially watered down cops.
Tracker is worth mentioning here as a major role - they track a player at night, and find out who they targeted but not what they did. Watcher is the other side of this, seeing all people who targeted their target.
Gunsmith is a particularly common watered-down-cop on SV - rather than getting a result of "Mafia" or "not mafia", they get a result of "Can kill" or "Can't kill."
Rolecop or Flavourcop is also worth mentioning. The former's invesigation gets powers, but not town/scum alignment; the latter just gets a clue from the GM, and has to figure out what it means on their own.
On the Informational side, we have the Innocent Child, Masons, Friendly Neighbour, etc - all roles that can mechanically confirm themselves as town.
Protective
The archetypal role here is the Doctor, who targets someone at night and prevents them from dying. Again, this is often watered down. The Bodyguard dies instead of their target if they are attacked: the Jailkeeper protects their target, but also prevents them from doing anything that night. Which is a good segue into...
Manipulative
Manipulative roles change how some other role works. The classic one here is Roleblocker, who prevents their target from being able to act on a given night.
Others that are common here are:
Busdriver/Transporter, who swaps two people in the night. Actions that target one instead hit the other.
Motivator, who lets someone else act twice in the night.
Killing
The classic one here is Vigilante, who kills in the night but is aligned with the town. A vigilante who wins if they are the last player alive is a Serial Killer.
Variations exist, such as the Trapsmith/PGO/Veteran, who kills everyone who visits them in the night, the Desperado, who shoots someone during the day and dies if their target was town, etc.
On that note, our final category:
Weird Shit
All roles can be modified, combined, etc, etc. This is where Jailkeeper, Gunsmith and Desperado came from, after all!
Have a look at Mafiawiki and you'll see that there are like a billion roles out there.
Most common here in the weird shit category are:
Jesters, who win by being lynched.
Cultists, who recruit instead of killing.
Various forms of private non-mafia chat. (Neighbourhoods, Covens, Masonries, etc.)
Gladiators, who get to force everyone to vote either for them or their target.
I don't think we tend to do anything that messes with alignments or reveals much here - Miller, Godfather, Janitor, Framer etc don't really exist. Post restricting roles don't tend to exist, but we do have occasional interaction with votes. (Bomb, doublevoter, etc.)
Of course, I could be super out of date here, but that's what I got in the back of my brain.