Stargate frequently use similar formulas with the bad guys, both in Atlantis and SG-1.
Goa'uld: "Hey, let's try out this Stargate thing!"
Parasites fostering a galaxy-wide false religion.
Would not have gone after Earth in the near future until earthlings started going after them.
Replicators:
A rare exception. Already fighting the Asgard, though every time humanity helps in the fight against them, they seem to get exponentially powerful.
Ori: "Hey, let's try this Ancient communication device!"
Ascended beings running a galaxy-wide false religion.
The Ancients shielded the Milky Way from their eyes until earthlings went and alerted them.
Wraith: "Hey, surely if we get our people back from this small group of Wraith and set some explosives, that shouldn't have had long term consequences."
Creatures who consider humanity their galaxy-wide livestock.
Earthlings raiding one of their hives inadvertently wake the wraith out of hibernation generations early, provoking most of the conflict with Atlantis.
Lately seem to have aquired worshippers to keep with the false god theme.
Asuran Replicators: "Hey, let's continue to pester these offshoots of the ancients, even though they clearly want us to go away."
Rehash of the replicators, mostly.
(Side Note:This always strikes me as the most annoying enemy, specifically in the ways the Atlantis team deals with them.
Even the Atlantis-friendly Asurans aside from Niam who were in the first episode were indiscriminately killed. For an enemy that seemed more interested in destroying Atlantis-the-city, rather than the human inhabitants...the earthlings always seem to be the ones escalating force in this particular conflict.
That, and despite having the super-cool name of "Asuran" in their intro episode, they are just called replicators every other time they are encountered. It bothers me

)
In any case, I have not seen the new episode yet, but will be watching it this morning. I am looking forward to this new-ish threat.