Some monsters have a "FREE" designation in their attributes in monsters.txt.
All black crayon monsters are missing this designation. I can't remember which (if any) wandering monsters were free fights, but the only things that are listed as such in monsters.txt are hipster fights, bricko fights, seal clubbing seals, halloween fights, skid row houses, and giant rubber spider.
All black crayon monsters are missing this designation. I can't remember which (if any) wandering monsters were free fights, but the only things that are listed as such in monsters.txt are hipster fights, bricko fights, seal clubbing seals, halloween fights, skid row houses, and giant rubber spider.