Template:Category
This is the Template UtfIcon it is good for showing arbitrary UTF character symbols see e.g.:
{{UtfIcon|utf=✓}}
✓
{{UtfIcon|utf=🌤|size=24}}
🌤
{{UtfIcon|utf=Δ|size=36|color=red}}
Δ
{{UtfIcon|size=48|color=blue|utf=♞}}
♞
{{UtfIcon|utf=☕|size=96}}
☕