Fiera Internazionale della Sardegna - Cagliari

 There are three flags on these 1998 Italian stamps: Italy, Sardinia (also know as 'The four moors flag'), and the European Union.

The stamp celebrates the International Fair of Sardinia, held in Cagliari every year since 1948 in its current form. I don't know if Italian stamps valued in lira are still valid as postage (there was a 2 euro stamp on the card also). 

And in the US flag stamps are ubiquitous. Here are two I received in the mail during the past two weeks.

On the left is 'U.S. Flag' designed from a photograph, issued in 2019, and on the right is a graphically designed 'U.S. Flag' issued in 2018. I hadn't noticed that they have the same name - in the past I remember the flag stamps having their own distinct names. The 2018 stamp takes its cue from another stamp issued in 2018 to commemorate the centenary of the Flag Act of 1818. The Flag Act formalized the design if the US flag - thirteen horizontal stripes and a star for each state - as well as the fact that changes to the flag after admission of a new state would always occur on Independence Day, July 4th.

Bonus:

Inspired by CJ's comment, here's more on the flag stamps issued by USPS over the last 10 years, and whether I am a fan or not. 

2020 "U.S. Flag stamped envelope". Graphic design.

No U.S Flag stamp issued (so far). There is a flag on the prestamped envelope - I am not a fan of this design (it reminds me of that roasting pan in the oven). The stars around the edge are a nice touch.

2019 'U.S. Flag'. Photo.

See main post. I wish there was less white space on the stamp.

2018 'U.S. Flag'. Graphic design.

See main post. It's OK, not my favorite of the graphic design flags. It's counterpart celebrating the Flag Act is a bit strange - that would be one oddly shaped flag if fully extended.

2017 'U.S. Flag'. Photo.

I like this close up detail of the flag.

2016 'U.S. Flag'. Photo.

Better than the 2019 design.

2015 'Stars & Stripes Presort Coil'. Graphic design.

There was no first class flag stamp issued, however there was a design of 3 stamps (that look best when seen together) at the presorted rate. I love this design, and would have enjoyed this at a first class rate.

2014 "Star-spangled Banner". Design created graphically from a photo.

This was different take on the more classic approach to flag stamps. I liked this one, and used it on mail. I remember some people not liking it because the flag was a little blurry. I believe the idea was to represent the flag in motion.

2014 "Red, white and blue". Graphic design.

This is my favorite of the graphic designs of the past 10 years. I remember reading some comments from people who despised them as too abstract. I believe it was only issued as a coil set. I bought a strip of them back when the post office sold strips of 20 stamps - not sure if the philatelic service still does that, lately I've been seeing strips of 500 being offered (coils usually come in 1, 5 or 10 thousand).

2013 "Flag for all seasons". Art design (possibly made/inspired by photos)

This was a nice take on a set of flag stamps, although hard to depict a difference from spring to summer though.

2012 "Four flags". Art design.

I believe this was a very popular set. I don't have a strong opinion on it.

2011 "Lady Liberty and Flag" Photo design.

I liked these stamps, although the Lady Liberty turned out to be a photo of an imitation in Las Vegas. Note that USPS since dropped the 'first-class' from their first class stamps, and just use the 'forever' term.

So it looks like giving (slightly) more descriptive names to the flag stamps stopped in 2016.

Explore more links to flags on postage at Sunday Stamps.