In case you didn't know, naming a tamed wolf 'Mars' in Snapshot 22w13oneBlockAtATime will give it a unique texture. I turned this feature into a resource pack, so you can do it on regular versions. The texture is directly ripped from the .jar file from its Snapshot, so I take no credit for it. This resource pack is for Java Edition only, I won't make a Bedrock Edition port.

Requirements for this to work:

• It has to be a tamed wolf.
• The name is case-sensitive. It has to be 'Mars' with a capital "M".
• Optifine is required.

This pack is for version 1.19. If you want to use it in a older version, open the .zip file, open "pack.mcmeta" and edit the entry "pack_format": X by replacing the X with the numeral that corresponds with the version you desire, by following this table's standards. It may not work on versions older than 1.14.