Contralto, Cupcake Slash and Coillapsia Slash are all property of WubcakeVA as is any art of those characters. The original pieces of art are here:
>>1323185:https://derpibooru.org/images/1323185
>>1125824:https://derpibooru.org/images/1125824
>>1450459:https://derpibooru.org/images/1450459
>>1268847:https://derpibooru.org/images/1268847
Actual full-size readable version here, since Derpibooru downsized it for some inane reason.
There’s a few errors I only noticed now:
Collapsia: “ot” should be “or”
Blending in: Should reference “Melodic Stage” instead of “Siren’s Stage”
Melodic Stage: “instead of sending it to the GY” is redundant, since Blending In is not a Field Spell.
Yu-Gi-Oh is, of course, © Kazuki Takahashi and Konami.