I don't know if there is a list but I can name a few:
geothermal:
PAX
GDY
PTR
TEY
GER
GRK
WAS?
EDE
hydrogen blend engines:
EDE
Solar:
DYE
Solar Tower
EVM (a real dog, don't know if it will get off the ground)
if you want to include cleaner coal techs:
ESI
underground coal gasification:
MEE
LNC
CXY
ICN? (I think they're ucg)
Fuel cells:
CFU
probably a lot more out there I don't know about.
