Fugitive of the Judoon gives you two creatures and a Clue token and cheats any doctor from your library into play
Illusionary Mask disguises our creatures (within their mana value) and, while we have to flip them up when they attack or do anything else meaningful, its still less information for our opponents to go off of
Generate and keep ticking up energy counts with Atraxa's proliferation effect, allowing you to use them for other effects
Read More: Wilds of Eldraine Is Warping Formats After Just Two Days #5 Spreading Seas Spreading Seas is an Aura with a rather unique effect
This means that if they have a removal or bounce spell, they can quickly take out Seizan and leave you down two cards in the exchange
Emet-Selch is a transforming card, meaning he has two sets of abilities that can be used, though once he's been transformed he can't go back