The fans of which band are called spuds?

Devo. According to Devo member Mark Mothersbaugh, the potato is part of Devo's philosophy, and the band have used potatoes in various ways throughout their career: the cover of their 1982 album "Oh No, It's Devo!" features the band members dressed up in potato outfits, they recorded a song titled "I'm a Potato," and Mr Potato Head featured in one of their music videos.

"We made potatoes part of the Devo philosophy and called ourselves spuds, both pejoratively and as a compliment," the band's Mark Mothersbaugh once explained, adding that potatoes represent "the dirty, hard workers of the earth" rather than "the aristocratic, above-ground fruits of the world".

Fans adopted the name out of affection to the above ways in which the band has used potatoes.

https://www.smh.com.au/entertainment/no-1-mash-hits-20030110-gdg33n.html