Thanks to the familiarity of Lego pieces, the 847-piece Lego Boost is one of the easiest and most fun to build among kits of its size. And because any Lego block can be used, there’s a massive opportunity for expansion right out of the box. The Lego Boost also has more add-ons than other kits we tested. Lego’s programming language is also graphical, using a library of recognizable symbols that you drag and drop to create command sequences. We recommend younger kids start off with a grown-up’s help; Wirecutter writer Signe Brewster can confirm that Boost is challenging and engaging for grown-ups, too.