Snake Umbra A little card draw goes a long way, and Snake Umbra has an incredible ceiling
The duplicate perpetually becomes a Robot artifact in addition to its other types
A fifth turn 4/4 flier is pretty beastly and one that doesn't have to tap to attack means that if this old girl survives combat, she can block on your opponent's turn
Underworld Dreams is basically half of Nekusar on an enchantment, very relevant if Nekusar starts drawing hate and gets to expensive to keep recasting
If you've spent a long time building your board and are desperate to protect it, this is a great way to do just that, as it's effectively a protection from board wipes and even outright game-over situations if you're low on health and under fire from your opponents
Despite the success of Wizards of the Coast's first-party online options in Magic: The Gathering Online and Magic: The Gathering Arena (which includes its own unique format, Alchemy), a lot of fans of in-person Magic will point to the unaffiliated card game simulator Cockatrice as the preferred method of online Magic play