Bayko were Bakelite, and relied on bars to hold the bricks together, I think metal and straight from a Meccano set. They may have even bolted to the base. (Bayko were another early product from Frank Hornby, maker of Meccano and Hornby trains). I think the sets were solely designed for making buildings with essentially all the pieces specialised.

There were plenty of others along the same lines that were building, house building or brick toys, but none had the self-assembly of the gripping pegs in the plastic bricks that became the Kiddicraft innovation, later copied by Lego. Earlier sets used, like Bayko, different materials and approaches to assembly and go back into the inter-war years, perhaps even pre-WW1.

Kiddicraft and Lego stem from injection moulding.