Games similar to Wiggles/Diggles/Gnomy include Widelands, which is free and open source. Other options are RimWorld, Dwarf Fortress, Oxygen Not Included and Valhalla Hills. In total there are five City Building Games like Wiggles/Diggles/Gnomy for Mac, Windows and Linux.
Widelands is a free, open source real-time strategy game with singleplayer campaigns and a multiplayer mode. The game was inspired by Settlers II™ (© Bluebyte) but has significantly more variety and depth to it. Still, it is easy to get started through playable tutorials.
RimWorld follows three survivors from a crashed space liner as they build a colony on a frontier world at the rim of known space. Inspired by the space western vibe of Firefly, the deep simulation of Dwarf Fortress, and the epic scale of Dune and Warhammer 40,000.
Canada
Dwarf Fortress is a single-player fantasy simulator. You can control a dwarven outpost or an adventurer in a randomly generated, persistent world. The world is procedurally generated with distinct civilizations spanning centuries of detailed history, multitude of towns, bodies...
United States
Oxygen Not Included is a space-colony simulation game. Manage your colonists and help them dig, build and maintain a subterranean asteroid base. You'll need water, warmth, food, and oxygen to keep them alive, and even more than that to keep them happy.
Canada
Valhalla Hills is a building strategy game in the tradition of games like The Settlers or “Cultures”. The player has to lead his outcast Viking heroes to the top of a mountain, where a magical portal is leading to Valhalla.
Germany
EU