Here are 2 all-plastic pins from Portugal. They are by Triunfo (probably "Triumph") likely give-aways with a product or some kind of purchase.

The pins are completely plastic, even the backing & the peg. This would likely make them pretty fragile & the backing easy to lose. The design appears to be an applied paper sticker for each one. The Tails looks quite like a piece of Japanese running-Tails stock art, but the other is clearly 100% Robotnik...interesting to get such a mash up of design choices. Also, if there's these 2 pins AND it's Sonic 3, you can bet there's a Sonic one & a Knuckles one as well. 

The third Triunfo pin appears, this time with poorly drawn Knuckles. They've chosen the rather off model look for him that was somewhat adopted by the UK Sonic the Comic, where his head is tall and his eyes are wierdly vertical. The fourth pin has to be Sonic, but Gear is still waiting for a photo of it.
Triunfo makes cookies in Portugal.

Sonic District found some extra images while porting this article from SonicGear to Sonic District! Here we can see the Sonic one that was missing, Knuckles in a sharper picture and even a Sonic & Amy one.