Is there a generic transistor symbol that is not specific to the transistor type?
In their book &quot;Feedback Amplifiers - Theory and Design&quot; (Kluwer, 2002), Gaetano Palumbo and Salvatore Pennisi describe their circuits by making use of a generic transistor that represents BJTs, HBTs, Mosfets and Mesfets.
The generic device of a given polarity is represented by this symbol (actually two, to consider the possibility of a substrate)

and is used in conjunction with &quot;a generic small-signal model applicable to a variety of different transistor types operating in the active region&quot; that is this one:

This 'unified' device is introduced

&quot;to ensure that all analytical results derived herein are applicable
to feedback configurations realised with both BJT and MOSFET
technologies –including heterostructure bipolar transistor (HBT) and
III-V compound metal-semiconductor field effect transistor (MESFET)
technologies.&quot;

and

&quot;is identified by four terminals denoted as X, Y, Z and B.
Specifically, X, Y, and Z respectively representing the emitter, base,
and collector terminals for BJTs (and HBTs) or the source, gate, and
drain of MOSFETs (and MESFETs). The fourth terminal B represents the
substrate or bulk node, it is almost always biased at a fixed
potential and conducts a negligible static current. Symbols X, Y and Z
were chosen to remind us of the functional equivalence between our
generic device and the negative second generation Current Conveyor&quot;

The first appearance ought to be in the paper
G. Palumbo, J. Choma Jr.,
“An Overview of Analog Feedback Part I: Basic Theory,”
Analog Integrated Circuits and Signal Processing,
Vol. 17, No. 3, pp. 175-194, Nov. 1998.