Bobicraft's Chimuelo

Chimuelo is a dragon mob that players tame with a saddle and a tail item. The taming recipe is taught in the mod's gallery, and taming progresses as the player approaches the dragon while holding the item. A tamed dragon can be sat down and stood up with shift-click, mounted with a click, and steered on the ground with the WASD keys. Holding Ctrl while moving makes it run, and a short tap of the space bar while running launches it into flight. In the air, WASD keeps the dragon hovering in place, and sprinting with Ctrl while moving makes it fly faster and follow the player's line of sight.

The author notes that a dragon can spawn when lightning strikes without a lightning rod nearby, with a 20 percent chance while another untamed dragon is present in the world. The mod is server required and client optional: the server needs it, while players may add it to their own game. It is distributed as a data pack, and the code is under the MIT License, but the project is not open source. Delete Dragon is required, because the riding dragon depends on it. Builds are published for Fabric, Forge, NeoForge and Quilt, all for 1.21.5, with v1.0.1 as the latest file.