You might use it in some sort of sacrifice combo deck (where it could still be broken), but simply playing it and hoping an opponent would kill the equipped creature wouldn't really be practical and would likely have kept Skullclamp from being ban-worthy
Likewise, if a delayed triggered ability that triggers "at the beginning of the next end step" is created during your first end step, that ability will trigger during your second end step
With a Teferi in play, you have the final say in what resolves and what doesnt since your opponents cant respond to your game actions
Get specific: Despite the temptation to include Myr creatures of all colors, it may help to decide on a specific strategy and build an Urtet deck to accommodate these situations
1 Selesnya Guildgate
With Green Slime, you can take out Lightning Greaves before it equips, smash Senseis Divining Top before it rearranges the deck, or even crush The Great Henge before it draws a card