  Direct-collapse black holes (DCBHs) may be the seeds of the first quasars,
over 200 of which have now been detected at $z > 6$ . The James Webb Space
Telescope (JWST) could detect DCBHs in the near infrared (NIR) at $z \lesssim
20$ and probe the evolution of primordial quasars at their earliest stages, but
only in narrow fields that may not capture many of them. Wide-field NIR surveys
by Euclid and the Nancy Grace Roman Survey Telescope (RST) would enclose far
greater numbers of DCBHs but only directly detect them at $z \lesssim 6 - 8$
because of their lower sensitivities. However, their large survey areas will
cover thousands of galaxy clusters and massive galaxies that could
gravitationally lense flux from DCBHs, boosting them above current Euclid and
RST detection limits and revealing more of them than could otherwise be
detected. Here, we estimate the minimum number density of strongly lensed DCBHs
and supermassive primordial stars required for detection in surveys by Euclid,
RST and JWST at $z \lesssim 20$. We find that for reasonable estimates of host
halo numbers RST, Euclid, and JWST could potentially find hundreds of
strongly-lensed DCBHs at $z = 7 - 20$. RST would detect the most objects at $z
\lesssim 10$ and JWST would find the most at higher redshifts. Lensed
supermassive primordial stars could potentially also be found, but in fewer
numbers because of their short lifetimes.
