The phrase "on the block" can be substituted with several other synonyms depending on the context. Some alternatives include "up for sale", "on the market", "available for purchase", "being auctioned", or simply "for sale". If the context pertains to a neighbourhood or street, suitable synonyms could be "on the street", "in the area", "within the vicinity", or "within reach". In the context of a business, one can use "available for acquisition" or "on offer". It is essential to use appropriate synonyms to ensure clear communication and avoid any ambiguity in the information being conveyed.