Use a counter to represent [creature]." Obviously "counters" and "tokens" became very different things, although that wording does harken back to how I suggested using dice as tokens in my above-mentioned teachings session
If it is Special Summoned, it can add a brand-new disruptive Trap Card: Virtue Stream , that allows you to destroy your Fish, Sea Serpent, or Aqua monster and wipe out two cards your opponent controls
Don't trade fake/custom cards for official cards
That creature package is backed up by a suite of all-purpose removal, Kaito and Sorin, and sideboard options that let you become a fairly decent discard-control deck in a pinch
They are classified in the main type-themed sections of the set and were represented by EX in the Black & White and XY eras, GX in the Sun & Moon era, and V in the Sword & Shield era