This beautiful dwarf nova has so far been observed by TESS in all of the northern hemisphere observational sectors released to date (sectors 14 to 18).
Dwarf novae are stellar binaries where one companion is a main sequence star and the other a white dwarf. In these systems material is transferred from the main sequence star to the white dwarf, forming an accretion disk and resulting in quasi-periodic outbursts, as seen in the lightcurve above. See https://blog.planethunters.org/2012/04/07/dwarf-novae/ for more details on these fun systems!
TIC 219107776 as seen on Planet Hunters TESS in Sector 18.