It’s consumer palpable which, depending on where you are, is something the average person doesn’t see the EU do a lot. The other big one would be EFRE funds with accompanying large posters saying this is paid by the EFRE funds but that’s kind of region specific.

Previous favourite would’ve been Schengen, but even removed from the fact that that predates the EU, it’s also a hard sell now that everybody is back to being used to backed up border crossings on account of getting too racist to keep one of the good parts of the EU going