well, as a quick guide, LIS is OK for some of it, but much reduced, these days.

Athens can be good, and easyjet single out
Italy can be popular for J to US, any starting point. Milan linate has the odd EZY single, but usually requires a nightstop, from memory but do check.
Malta similar but singles may take some thinking about.

If you were heading for Utah, you might be heading for Chicago rather than Dallas on AA connections. Not really thought about it but it should be worth bashing in WAW as a starting point as LOT fly to Chicago, from memory.

However, there are enough tools around to do the job, rather than relying on my memory.

Just changed my computer so the new favourites are not in yet.