Over at Airframes, we are trying to make some aviation data more available and easy to use. In some cases, we have written scripts to pull some some official sources, and then rewrite out into standard formats (CSV, JSON) on a regular basis (automated using GitHub Actions).
If you grab the Raw urls (clicking the Raw button on these GitHub pages) you can get the direct link to the content and use them in your apps.
Country-specific Airframe Registrations
Airports
Fixes/Waypoints
AIREP/PIREPs
TFRs
METARs
SIGMETs
TAFs
ACARS Ground Stations
VDL Ground Stations
HFDL System Tables
I will update this post with additional data sources we provide as they become available.