Moving from Lego, another popular with us that I see is still going was fischertechnik (
https://www.fischertechnik.de/en) which I guess we found mid 70s. Like Lego, it seems to still exist but to have moved on a bit. At the time or at least with what we had, I’d probably describe it as a cross between Lego and Meccano. Its plastic parts and ease of assembly were closer to Lego but the parts enabled more of the (let’s call them) engineering type structures that (to me fiddly and I never really took to) Meccano enabled. I’m not sure those of us who enjoyed Lego would ever completely outgrow* it but for me, probably around 15 at the time, it did feel like a bit of progression.
* I guess I could still play with plain Lego blocks now although I’ve gone with something more modern to play with recently. I’ve got an Arduino kit to play with. I can to some degree program and do some basics but focus has always been on working out something for a home project rather than having a pack of input and output (eg. sensors and motors) to learn play with and experiment with. It’s hard really to relate what is around now to my own (b 1960) childhood. I guess one could argue that one could do more with less back then and that imagination (eg. with the build stuff, a blocky Lego “aeroplane” could seem “real”) played a greater part but I can also wonder what childhood would have been like for a (in my case only slightly and, like Fester, I also enjoyed outdoor things) more geeky child with the stuff available now back then...