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We report on the spectroscopic confirmation of 68 new bright ($G=13.5-17.2$mag) and blue (pre-)white dwarfs (WDs). This finding has allowed us to almostdouble the number of the hottest ($T_{\mathrm{eff}} \geq 60$kK) known WDsbrighter than $G=16$ mag. We increased the number of known ultra-highexcitation (UHE) WDs by 20%, found one unambiguous close binary systemconsisting of one DA WD with an irradiated low-mass companion, one DAO, and oneDOA WD that are likely in their transformation phase of becoming pure DA WDs,one rare, naked O(H) star, two DA and two DAO WDs with $T_{\mathrm{eff}}$possibly in excess of 100kK, three new DOZ WDs, and three of our targets arecentral stars of (possible) planetary nebulae.  Using non-local thermodynamic equilibrium models, we derived the atmosphericparameters of these stars and by fitting their spectral energy distribution wederived their radii, luminosities, and gravity masses. In addition, we derivedtheir masses in the Kiel and Hertzsprung-Russell diagram (HRD). We find thatKiel, HRD, and gravity mass agree only in half of the cases. This is notunexpected and we attribute this to the neglect of metal opacities, possiblystratified atmospheres, as well as possible uncertainties of the parallax zeropoint determination.  Furthermore, we carried out a search for photometric variability in ourtargets using archival data, finding that 26% of our targets are variable. Thisincludes 15 new variable stars, with only one of them being clearly anirradiation effect system. Strikingly, the majority of the variable starsexhibit non-sinusoidal light-curve shapes, which are unlikely explained interms of close binary systems. We propose that a significant fraction of all(not just UHE) WDs develop spots when entering the WD cooling phase. We suggestthat this could be related to the on-set of weak magnetic fields and possiblydiffusion.

The bright blue side of the night sky: Spectroscopic survey of bright and hot (pre-) white dwarfs