Mac OS X Softwares to Moddable

Clonk is an engaging 2D action-strategy game series combining exploration, crafting, and survival elements. Players control small, versatile figures known as Clonks, navigating diverse landscapes to gather resources, build structures, and interact with the environment and other players in both single-player adventures and dynamic multiplayer matches.

Starbound is a 2D extraterrestrial sandbox adventure game where players explore vast procedurally generated planets, build bases, craft items, and uncover the secrets of the universe following their ship's destruction.

RimWorld is a story generator driven by an intelligent AI storyteller. It simulates a sci-fi colony, challenging players to survive on a distant planet by managing colonists, building a base, researching technology, and defending against various threats.

Mythruna is an ambitious sandbox RPG blending deep role-playing elements with an infinite, procedurally generated world. Players can explore, craft, build, and shape their environment through a rich modding system, offering a truly dynamic and personalized experience.

Voxelands is a free, open-source voxel game inspired by Minecraft, offering creative construction, survival challenges, and exploration in expansive, procedurally generated worlds. It supports both single-player and multiplayer modes, allowing for collaborative building and adventure.

Junk Jack is an action-adventure sandbox game where players explore procedurally generated worlds, build elaborate structures, mine resources, and craft a vast array of items. It combines elements of survival, exploration, and creative building in a vibrant pixel-art environment.

osu! is a vibrant, community-driven freeware rhythm game where players tap, drag, and spin to the beat of their favorite songs. With a massive library of user-created beatmaps and multiple gameplay modes, it offers a challenging and engaging experience for both casual players and competitive enthusiasts alike.

StepMania is a versatile, open-source rhythm game engine and simulator, primarily known for replicating the arcade dance experience. It supports a wide range of input methods and game modes, allowing players to enjoy rhythm gaming on their own terms.

Roblox is a global platform uniting people through play. It is powered by users, offering an ever-expanding universe of immersive experiences created by a community of millions of developers and players.

King Arthur's Gold is a retro-inspired 2D online multiplayer action game blending combat, building, mining, and resource management. Players engage in large-scale battles across destructible environments, constructing fortifications and sieging enemy castles in a medieval setting.

Minetest is a free and open-source voxel game engine, similar to Minecraft. It allows users to build various structures, explore vast, procedurally generated worlds, and engage in survival-based gameplay or creative construction. Its strong emphasis on modding and community contributions provides a highly customizable and extendable experience.

OpenTTD is a free and open-source simulation game where players build vast transport networks to manage goods and passengers, mirroring the classic Transport Tycoon Deluxe with enhanced features and multiplayer support.

Terraria is a 2D sandbox adventure game where players explore vast procedurally generated worlds, build structures, craft items, and fight a variety of enemies and bosses. It's known for its rich content, deep progression system, and strong emphasis on exploration and creativity.