(We've also finally added Meltan and Melmetal too! Sorry that took so long!)
With the Pokémon games getting more complicated and relying on 3D models, the style no longer fully fits with our Gen 3 (released over 15 years ago!) style Trainer Cards, so this time we've added both the in-game 3D models used for the Pokémon and the new, bigger, more detailed menu sprites to choose between. We're also waiting on being able to add Shiny forms and some alternate forms (such as the bazillion Alcremie forms), so we don't currently have that available - but we should do in a future update.
A wider-ranging update to both the Trainer Card Maker and the website itself are both in the early stages of development. The next major update to the TCM is likely to be during or after this work goes live sometime next year. Please bear with us until then.
As with any major update, there's a chance a few issues might have crept in, so please let us know if you run into any trouble with using the new Pokémon in your Trainer Cards!