Lol, by the time I finally do get that last bp, I'll probably have given up on Iron Age and moved on.
P.s. This is not ment as whining, lust laughing at my luck, and btw. we say: luck in love, bad luck in games.
It's that way with all the buildings. You have two choices: Keep collecting blueprints so that eventually you get that missing on; or try trading them on a 2:1 basis (meaning you lose one on every trade with no guarantee you will land the right one either!).
Pick your poison.
On the other hand, you also do not need to rush through Iron Age and move on.
Rushing through any age is the biggest mistake you can make in this game. Each GB is age specific so aiding buildings from its age will help. So the further you move up away from the early ages the harder it is to get the BPs for those ages.. Zeus for instance is a Bronze age GB so aiding Bronze age buildings will help you get BPs. If I remember correctly the best BA buildings to aid for Zeus are stilt houses, theatre, school, flower deco and blacksmith. The other BA buildings are better to get ToB Bps. But INNO does that with every GB, they make sure you are left waiting on one for ages with the hopes you will give in and spend diamonds to get it LOL Unless it is for the likes of Col which you will never build.
True, have Col and ToB sitting as completed bp-sets... not planning on building those.
And yes, did learn not to rush hard way... now I'm struggling to get my ba mats... luckily I did get the message before rushing to Early Middle Age, and opening myself to raiding. lol