Although the PCG is a game in it's own right, PGC cards are not legal in the Yu-Gi-Oh!™ TCG or any other card game at this time. Every card is designed to, in some way, make light of real trading card game cards or mechanics. Card artwork is either used in parody, or with permission of the respective artist. To see how these cards were made, or to make your own Yu-Gi-Oh! cards, go to www.yugiohcardmaker.net. The Trigamon PCG is free, and is designed to always be (with the exception of physical resources) so you can enjoy without paying for scraps of paper.
I hope they will be tournament legal at some time in the future, but I cannot make promises. There is no timeline as there are no negotiations ongoing. Feel free to negotiate with Konami on our behalf or, alternatively, lobby congress to pass a bill regarding card game tournaments.
Note that many of the cards in this set are not displayed because they do not have artwork. If you are interested in doing the artwork for these cards, PLEASE contact me. All artwork displayed on these cards is the property of the artists, not me (except of course where I am the artist). And of course some existing artwork is used, but only strictly in parody.
(If you submit artwork for a card, you still own the artwork, all you are doing is giving Trigamon permission to use it)
One final note is that you can tell Trigamon Cards from Yu-Gi-Oh!™ cards by looking at the year they were released. Trigamon Cards are copyright by their inventor and the year that they were made. No Trigamon cards were made in 1996.
Several cards use free images from Pixabay, however after stumbling upon an image of the Pokemon Snowrunt, it has come to my attention that there still might be copyright issues. If you see your artwork on a card that doesn't specifically say that artwork is used in parody, please email me so I can take the card down or replace the image. Also please provide proof of your copyright, otherwise I might not be able to verify the copyright claim.