Kinda?

But only for generic blocks. There’s been copycats as far back as I can recall, with varying degrees of compatibility. They all more or less have fit, but that more or less could be pretty damn far apart. I can’t recall brand names though; and the only box I have of them is shoved in the back corner of the attic since I don’t currently have anyone in my that’s into the standard old school lego blocks. The Lego fans I know are into specific kits rather than freeform building in primary colors lol.

Never ran into any that you couldn’t make work with actual Legos, but some that wouldn’t work with each other.