This gives you the full system built to help you lay out the set correctly, track it cleanly, and know exactly whats missing
Tocasias Welcome is my current pick, for a couple reasons mainly that it triggers off of tokens, and because it triggers on opponents turns, and because enchantments tend to stick around longer than creatures
[W][C][C][C][C] Hydro Splash: 180 damage
Look for Holo Rare, Ultra Rare, and Secret Rare cards to spot valuable ones
If that wasnt all, though, Gholdengo exs Alternative Art is part of a double-card artwork, similar to the Illustration Rare version of Tarountula and Spidops: when paired with the Illustration Rare version of Gimmighoul, the two cards form a single beautiful card that any collector would love to have
The idea is to play a bunch of cheap artifacts like [c]Memnite[/c] and [c]Ornithopter[/c], then to play affinity cards like [c]Thought Monitor[/c] for very low mana costs