A lot of these projects will probably come down to funding priorities and population growth over the next few years. Highway 413, the Bradford Bypass, the 427 extension, and GO Transit expansion seem to get the most attention because of their potential impact on growth across the GTA.
For anyone interested in how transportation infrastructure affects development and housing demand across the region, this GTA-Homes article provides some useful context:
https://www.gta-homes.com/real-estate-info/what-are-transit-oriented-communities/
Major transportation projects often end up shaping where future housing and employment growth occurs.