RewindRewind's four-mana cost can be a bit unwieldy at times, but if you can find a deck that's comfortable with holding it up, it's hard to beat RewindRewind for brute force at a discount
I started thinking about rituals, or temporary and burst ramp
It also nullifies your opponent's graveyard - pretty backbreaking for strategies like 'Dredge' that rely on the 'yard - and allows you to grab your opponent's best threat from the void and play it free of charge (Okay, at the cost of its own life, but it's a lowly two-drop, so who cares?) Paired with targeted discard cards like the popular Thoughtseize, Dauthi Voidwalker has the potential to be super scary
Best Cards: Shiko and Narset, Unified got a bad deck, but is a pretty cool commander with lots of flexibility
Captain Hook, Forceful Duelist is a decent card that costs just 1 Ink to get into play, but you can also use him in your Inkwell as a resource too, if you choose to