CA3140 and CA3130 are originally RCA part numbers( i feel). They are amazing close to ideal opamps, the input offset has to be trimmed. I used to use it when high input impedance is required. 1.5T ohm 10pA is the specs. A Electrometer can be made with just one opamp.
CA3130 has the additional Merit of swinging to the rails, if you are on a +/- 12V supply, the output will be +/-12V. This is a feature required in control applications.
“15MHz, BiMOS Operational Amplifier with MOSFET Input/CMOS Output
A CMOS transistor-pair, capable of swinging the output voltage to within 10mV of either supply-voltage terminal (at very high values of load impedance), is employed as the output circuit.”