Look for "Cloud Art" on the X-Plane.org forums. It replaces the default "puffy" clouds with high-resolution textures that look much more natural.
Flying over blurry ground textures is a mood-killer. Here is how to fix the world. x plane 11 addons freeware free
Search for any scenery by MisterX6. His freeware airports (like Boston Logan or San Francisco) are legendary for their detail and performance optimization. Look for "Cloud Art" on the X-Plane
Here is the definitive breakdown of the best to download right now. 1. The Must-Have Aircraft Here is how to fix the world
This is the gold standard. It takes the default X-Plane 737 and turns it into a professional-grade simulation with a fully functional FMC, custom sounds, and realistic flight dynamics.
The best place to start is the under the "Downloads" section. It is the hub for the community and hosts thousands of free files. Always check the "Top Rated" or "Most Downloaded" filters to find the hidden gems.