Some thoughs:



Rockery - im fine with researching marketplace techs.



Strongholds - never used it. Siegie dosnt work currently i suppose.



Unit - Healing units so they not die but collect experience is useful, the problem is that Shaman misbehave. Sometimes it attacks own troops, or try to heal unit which is full health. Officer is mobile, and with 2h weapon quite effective. Necrodrone is effective.



Public Library - the flat value and bonus are sick. Very good. Maybe too good.



Alchemist Furnace - must have.



Center for Seas nad Rives - very interesting tech opening some coastside city opportunities (with dust collectors). Unfortunetly never pull it off.



Mill Foundry - crazy good, funny thing that later tech gives some % but without flat value for much more production.



Advanced Armors/Alloys/Fillgree - never research this, since it is hardly possible to research, build collector, build army, and grab enought gold to upgrade your troops, it is much easier fast run to second era. Something should be done with it.



Sewer System - is fine.



Search Party - fun tech, probably allowing some crazy opening, but hardly ever used it.



Language Square - parley quests are fun.



Empire Mint - another must have.



Seed Storage - another must have.



There is general problem that Empire Mint, Mill Foundry, seed storage and Public Library are soo good. That you shooting yourself in the knee if not taking them asap. And they are all cheep to sustain. I think it would be better if they have just raw numbers without % bonuses, so it will be the way to deal with bad location.



Dust Dredger - very useful, potencially powerfull if on river, often i can catch many tiles with it (double rivers). Possible nice synergy with Center of Seas and Rvers.



Open Pit Mine - nothing to say, just get it.



Prisoners, Slaves and Volunteers - interesting technology, possible effective with good focus on gold, or some ruin hunting.



Top 8:

Mill foundry

Seed storage

Empire Mint

Alchemist Furnace

Open Pit Mine

Public Library

Sewer System

Rookery

(to be honest this one are core)



The last one:

- Language parley, potencially very useful, since quests are fun and it gives free population. However you may have other plans than running for quests.

- Unit, could be useful (necroprobes) but could be simulated with minors.

- Tresure hunting, fun but you may want your troops to do parley quests.

- Dust Dredger - there is pleanty of rivers

- Prisoners... possible very powerfull, however i ended using my gold upgrading trops.

- Center of Seas - possibly potent with good location...but never used it.



Tier 1 glasssteel/titanium are waste, it will not work.

Besieging currently dosnt work.