Since 2006, CCP has given out medals to winning teams in the yearly alliance tournaments. Gold, silver and bronze medals exist. In later years it was in sets of 3 x 12 medals, as each team could hold 12 pilots.
The medals are not inscripted with year, so gold-gold or silver-silver are interchangeable from any year.
The last year the medals were awarded was the latest tournament in 2018 (?).
All in all there are maybe c.300 medals that have been awarded(?). Unlike the Alliance Tournament Cup, the medals can be freely traded. Given their sentimental value, they are rarely seen for sale and fetch billions of isk.