No, YBZ does not have a lounge, because YBZ is not an airport at all: it is a rail and bus code assigned to downtown Toronto, used by booking systems to cover ground transport rather than a runway or a terminal. If you searched for a YBZ airport lounge expecting gates and a boarding pass, there is nothing to find under that code, but Toronto itself has two real airports with a genuine lounge picture worth knowing before you travel.
Toronto Pearson International Airport (YYZ), the region's major hub, is where the real lounge access actually lives. Air Canada operates Maple Leaf Lounge locations for its own elite status holders, Aeroplan tier members, and eligible premium-cabin tickets, spread across Pearson's terminals. Plaza Premium also runs pay-in and Priority Pass lounges at Pearson, open to a broader mix of travellers who hold a qualifying membership or are willing to buy a day pass at the door. Between the two operators, most travellers flying out of Toronto proper have a workable lounge route if they hold the right credential.
Billy Bishop Toronto City Airport (YTZ), the small downtown airport on the Toronto Islands, is the closer option if you are actually near the downtown core rather than out at Pearson. It runs a modest lounge-style space for its own premium and status passengers, scaled to a single-runway city airport rather than a major international hub, so temper expectations against Pearson's larger offering.
Because access rules and even lounge locations shift over time at a hub as large as Pearson, confirm your specific eligibility, whether through Air Canada status, a premium fare, or a Priority Pass membership, before you fly. If YBZ was your starting search term, the practical takeaway is simple: redirect your lounge planning to YYZ or YTZ, and match your credential to whichever of the two you are actually departing from.