A lot of the potentially scary cards from the new set can be dealt with via Decay as well such as Prophetic Flamespeaker and Dictate of Kruphix
The face commander, Kotis, Sibsig Champion, also has potential as an infinite-sized beater with the right recursive loops in motion
Plus, Ive found the community is always happy to help newcomers
For any card printed since 1998, you have two clear indicators: The Set Symbol Color: The most immediate visual cue is the expansion symbol, located on the right side of the card, between the art and the text box
That has a lot of options, especially as you can copy a non-creature artifact like Spine of Ish Sah or Gilded Lotus
If you have Bruna, the Fading Light or Gisela, the Broken Blade as your commander and meld them, the melded creature is still classed as your commander