I think, (trying to follow this) the seats come from: the right (Yamina, Yisrael Beytenu, New Hope), center (Yesh Atid, Blue and White) and left (Labor, Meretz), and from the Arab Ra’am party. Ra’am has four MK seats, and that pushes the total over 60.
It strikes me as the kind of alliance united by a single goal; get Netenyahu out of office and as a defendant before a jury. Once that happens I don’t see it lasting very long.