there are cards for enemies (rare drop chance but the combo move Negotation between frisk and nazrin can get you them easier) and if you collect them all and take them to the black market it opens a secret room, which has another fishing spot
Since you can easily edit the game's files, I just made a copy of "game\re_curse\Graphics\SFonts\slightglitch_SFont.png" and renamed it to replace "glitch_SFont.png" in the same folder in order to decipher all of that.
