  We present BVRI and unfiltered Clear light curves of 70 stripped-envelope
supernovae (SESNe), observed between 2003 and 2020, from the Lick Observatory
Supernova Search (LOSS) follow-up program. Our SESN sample consists of 19
spectroscopically normal SNe~Ib, two peculiar SNe Ib, six SN Ibn, 14 normal SNe
Ic, one peculiar SN Ic, ten SNe Ic-BL, 15 SNe IIb, one ambiguous SN IIb/Ib/c,
and two superluminous SNe. Our follow-up photometry has (on a per-SN basis) a
mean coverage of 81 photometric points (median of 58 points) and a mean cadence
of 3.6d (median of 1.2d). From our full sample, a subset of 38 SNe have
pre-maximum coverage in at least one passband, allowing for the peak brightness
of each SN in this subset to be quantitatively determined. We describe our data
collection and processing techniques, with emphasis toward our automated
photometry pipeline, from which we derive publicly available data products to
enable and encourage further study by the community. Using these data products,
we derive host-galaxy extinction values through the empirical colour evolution
relationship and, for the first time, produce accurate rise-time measurements
for a large sample of SESNe in both optical and infrared passbands. By modeling
multiband light curves, we find that SNe Ic tend to have lower ejecta masses
and lower ejecta velocities than SNe~Ib and IIb, but higher $^{56}$Ni masses.
