@Blue Ghost @pineappledan @adan_eslavo
Any building that provides an:
instant boost yield
WLTKD
GPP
Carthage: Tophet (Culture on unit purchase)
Arabia: Madrasah (Science on unit/GP faith purchase)
America: Ranch (Food and Culture on border growth)
Byzantium: Hippodrome (WLTKD on construction/event)
Babylon: Etemananki (Food and Science on building purchase)
China: Examination Hall (GPP on citizen birth)
Huns: Alti Cur Council ( Science and Gold on tribute)
Maya: Pitz Court (Faith and Science on bak'tun)
Mongolia: Yassa Court (WLTKD on city conquest)
Persia: Pairidaeza (Culture on GA)
Polynesia: Fale Te'le (Culture/Gold/Faith/Faith on building construction)
Siam: Baan Chang (Culture on CS gift)
Sweden: Sauna (Science/Culture on citizen birth)
Zulu: Iziko (Culture on promotion)
Not a building but a unit I saw that wasn't implemented yet I think
Japan: Yamato (Culture/GAP on completion/destruction)
To address your note, GPP thresholds are indeed increased on Epic/Marathon as well as WLTKD durations. This should make sense, as the benefits should remain proportional with respect to time.