A next field of conflict is Belarus, which tries to distance itself from Russia. It's not NATO, it's not a country with a security guarantee like the Ukraine ( https://en.wikipedia.org/wiki/Budapest_Memorandum_on_Securit...) , it's not trying to connect itself to the EU (like the Ukraine), but still it could be a next conflict.
Then there are European countries not in NATO, but cooperating with NATO, like Sweden and Finland. Both have a border with Russia.
Sweden doesn't have a border with Russia. Also, as a Finn, I highly doubt Russia would attack Finland. We have a relatively good relationship with them, and such a war would be very costly with nothing to be gained. If there was a larger conflict in Europe, Russia might try to invade Åland or Gotland, but that also sounds unlikely to happen.
Belarus, really!?! They look like a fragment of the USSR that simply hasn't gotten the message yet. Where's the burgeoning democratic movement, where's the economic modernization?
Then there are European countries not in NATO, but cooperating with NATO, like Sweden and Finland. Both have a border with Russia.