I understand Turkey and Tunisia are two of the countries.
As for the others, I can't see Ryanair starting to Algeria or Libya. Most former Soviet republics are either in the EU or too far east for Ryanair, so that leaves Russia, Belarus, Ukraine and Moldova. You can probably rule out Belarus. So, pick three of Egypt, Russia, Ukraine and Moldova.
I had heard Israel mentioned as a possible, but can't see it personally, considering the extra security on Israeli flights and what that could do to costs and turnaround times.
cesare.caldi->These are dependent on those countries agreeing to open skies with the EU.