Various new physics models can be tested via primordial black hole searches as well as the primordial black hole itself is a good dark matter candidate. In this talk, I will shortly introduce various primordial black hole formation mechanisms in cosmological first-order phase transitions and will focus on the mechanism where primordial black holes are formed by bubble collisions. For this mechanism to work, symmetry-breaking bubbles need to be super-horizon-sized and not run-away. The PBH abundance can be estimated by counting the number of such collisions of large bubbles for a given first-order phase transition. It will be shown that various PBH searches already rule out a part of the effective parameter space of first-order phase transitions, and another part can result in PBHs to be the whole dark matter.