[Vuejs]-Vuetify v-for change v-icon color

You could use CSS to style the icon’s background, using the .mdi-instagram selector:

<template>
  <v-icon>mdi-instagram</v-icon>
</template>

<style>
/* https://stackoverflow.com/a/44940095/6277151 */
.mdi-instagram {
  background: radial-gradient(
    circle at 30% 107%,
    #fdf497 0%,
    #fdf497 5%,
    #fd5949 45%,
    #d6249f 60%,
    #285aeb 90%
  );
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
</style>

Result:

demo