Sprinkle the gelatin powder over the cold water in a bowl and let it bloom for 5 minutes.
Pour the boiling water over the bloomed gelatin and stir until fully dissolved.
Stir in food coloring gels until desired colors are achieved and add corn syrup if using.
Pour the mixture onto a parchment-lined baking sheet in a thin, even layer.
Allow the gelatin to set at room temperature for several hours until firm.
Use small cookie cutters or a knife to cut out sequin shapes.
Carefully peel the sequins from the parchment paper.
Store in an airtight container until ready to use.