as to Op Amps, I only know tl061 as a usable low current (higher noise) one...
These things are never clear cut as you are trading supply current vs noise and other performance limits.
I can only outline the main points
(In the datasheets) Tabulated currents are higher than graphs as tabulated currents are for full temperature range.
Opamp Current Type Noise Comment
TL061/62 175uA typ. @ 10V, 25C (per amp) JFET 40nV/rtHz ;base-line
LF441/42/44 150uA typ. @ 10V, 25C (per amp) JFET 35nV/rtHz
LM4250 ~50uA (Iset=10uA) BJT 40nV/rtHz ;(noise in NatSemi 2000 datasheet)
MC1776C ~85uA (Iset=10uA) BJT 32nV/rtHz
TLV170/2170 107uA typ. @ 10V, 25C (per amp) FET 22nV/rtHz ;good modern, SMD only
MC34181/82/84 210uA typ. @ 10V, 25C (per amp) BJT 38nV/rtHz ;not that great
MC33178/79 380uA typ. @ 10V, 25C (per amp) BJT 7.4nV/rtHz ;no single version
The LF441 etc was one of the better older op amps with low power and low-ish noise.
The LF442 is used in the HAZ/Fodera/Ken Smith bass preamps.
There's a trade-off between noise and current draw. The MC1776C is similar to the LM4250.
You can see the MC1776C has a higher current draw for the same Iset and that the noise voltage is lower.
The TLV170 is a more modern design and only available in SMD. Slightly more current than the MC1776C,
but still low, and a good trade-off for even lower noise.
TLV170 datasheet does a good job explaining the isolation resistor requirements when driving capacitive loads.
See figure 32, CL=1n => Riso = 250 ohm (pm=45 deg), Riso = 700 ohm (pm=60 deg).
The figure cannot be used for other op amps.
https://www.ti.com/product/TLV170
The MC33178 has no single op amp equivalent. You can see the supply current is quite a bit higher
but the noise is reduced to quite low levels.
For low current op amps be conscious of:
- higher output impedance, less ability to drive capacitive loads.
- require higher resistor in series with the output (Riso) to drive capacitive loads.
Could be 1k or more.
- limited slew-rates
- slower recovery from overloads
If you do you own buffer from transistors then you really should place a resistor in series with the output to ensure it doesn't oscillate. A value of 1k is probably OK but beyond that nominal value it gets a bit technical.
It is possible to add a push-push stage to a DIY design You can use the same trick that the LM4250 uses ie. large resistors on the emitters of the output transistors. The circuit obviously starts to grow and that will push you back to using an opamp :0. A circuit sort of like RG's operating at 100uA to 200uA is in the right zone without going push-pull.