Warcraft 2 / Starcraft type games ( or clones, or engine recreations )
Im missing a lot of charm that w2 and first starcraft games had, and i did not see any open engine recreations, nor clones that lived to this day. With warcraft 3 i only ever finished half of the game, by the time sc2 came out, i was already too old to even bother trying.
I don't know that I would call Northgard a Warcraft clone. The mall is divided into tiles and each tile has its own resources and building limits. Units can only attack other units that are in their tile. There's a much bigger emphasis on building up your tech tree and taking tiles.
Still, it's one of the more interesting and fun evolutions of the RTS genre. If sci-fi is more to your taste, Dune the newer gameby the same studio is similar.