  Despite metals are believed to be insensitive to field-effect and
conventional Bardeen-Cooper-Schrieffer (BCS) theories predict the electric
field to be ineffective on conventional superconductors, a number of gating
experiments showed the possibility of modulating the conductivity of metallic
thin films and the critical temperature of conventional superconductors. All
these experimental features have been explained by simple charge
accumulation/depletion. In 2018, electric field control of supercurrent in
conventional metallic superconductors has been demonstrated in a range of
electric fields where the induced variation of charge carrier concentration in
metals is negligibly small. In fact, no changes of normal state resistance and
superconducting critical temperature were reported. Here, we review the
experimental results obtained in the realization of field-effect metallic
superconducting devices exploiting this unexplained phenomenon. We will start
by presenting the seminal results on superconducting BCS wires and
nano-constriction Josephson junctions (Dayem bridges) made of different
materials, such as titanium, aluminum and vanadium. Then, we show the mastering
of the Josephson supercurrent in superconductor-normal metal-superconductor
proximity transistors suggesting that the presence of induced superconducting
correlations are enough to see this unconventional field-effect. Later, we
present the control of the interference pattern in a superconducting quantum
interference device indicating the coupling of the electric field with
thesuperconducting phase. Among the possible applications of the presented
phenomenology, we conclude this review by proposing some devices that may
represent a breakthrough in superconducting quantum and classical computation.
