These include creatures such as Agent Frank Horrigan (indestructible, proliferate), Alpha Deathclaw (destroys permanents), Consuming Aberration (mill), Ezuri (proliferate, card draw), Fathom Mage (evolve, card draw), Lily Bowen (+1/+1 counters, life gain), Marcus (card draw, +1/+1 counters), and many more
Its not necessarily a good card if you are ahead or at parity, and even if youre behind, your opponent still gets to keep their best permanents
Those days are gone, thanks to cards like Urza, Lord High Artificer that make it completely one-sided
Beyond that triggered ability, Sixs main effect is likely giving all nonland permanent spells in your graveyard retrace, which allows you to replay them by simply discarding a land card from your hand in addition to paying their mana cost and any other costs associated with the card
In other words, Ixalan was being used to flavor what was originally its own separate world
And while there are a couple of Clue cards that are artifact creatures, like Red Herring, by default most clues are just artifacts, not creatures
