Unlit/Transparent Cutout をベースにしています

CustomUnlitTransparentCutout.shader

// Unlit alpha-cutout shader.
// - no lighting
// - no lightmap support
// - no per-material color

Shader "Custom/Unlit/Transparent Cutout" {
Properties {
    _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
    _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
}
SubShader {
    Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
    LOD 100

    Lighting Off

    Pass {  
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 2.0
            #pragma multi_compile_fog
            
            #include "UnityCG.cginc"

            struct appdata_t {
                float4 vertex : POSITION;
                float2 texcoord : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f {
                float4 vertex : SV_POSITION;
                float2 texcoord : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                UNITY_VERTEX_OUTPUT_STEREO
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            fixed _Cutoff;

            v2f vert (appdata_t v)
            {
                v2f o;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
                return o;
            }
            
            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 col = tex2D(_MainTex, i.texcoord);
                clip(col.a - _Cutoff);
                UNITY_APPLY_FOG(i.fogCoord, col);

                float edgeHeight = 0.015;
                return lerp(
                    col,
                    fixed4(0, 4, 2, 1),
                    step(col.a, _Cutoff + edgeHeight)
                );
            }
        ENDCG
    }
}

}