I guess the only game where you can really do anything is DnD.
Stop playing a game that causes cancer and instead pick up a game where you really can do anything.
ShadowRun (where hacking into the bank's security system, shooting the guards, and stealing the gold never felt so good).
Oh, you can still go dragonslaying if you want, but I don't recommend it. They're like D&D dragons on crack, and that's just the small ones. The metaplot important guys (who have names and are older than religion) tend to have game breaking powers (above and beyond ignoring most of the rules for Magic--they're still subject to how much of it they can throw around at a time and take drain damage for doing so, but they know all spells and they're free to invent new ones on the fly*).
For a power comparison: a starting points SR character can beat up a modern swat team without breaking a sweat.
A "low on the totem pole" dragon can beat up a starting points SR team without breaking a sweat.
A great dragon can beat up whole countries (though usually they don't, its not very profitable, and besides they're trying to be humanity's guardians).
Non-great dragons are subservient to great dragons, for the most part. There isn't a lot of information on them, actually. They're not metaplot important (eg. literally running the world) and are of such sheer power that your main characters in fiction aren't likely to meet up with them often. Great dragons take the spotlight because they are like hurricanes: a force of nature, manifested. A great dragon donates $100,000,000,000 to cancer research? People notice.
*Inventing new spells does have rules (and normally takes weeks), but in the official fiction great dragons seem to not be bound by them. Though they're still not allowed to teleport or raise the dead. No one is allowed to do that.