They might be stealing the cards put into graveyards with Captain N'ghathrod or taking advantage of the way it interacts with Zellix, Sanity Flayer, for example
To get to a place in which you can play it, though, youll need cards like Prismite and Prophetic Prism, which allow you to pay mana in order to gain mana of any colour, and Skittering Surveyor, which lets you look through your deck for a land card of your choice and put it in your hand
As for an attacking Glimmer, Lyle Tiberius Rourke - Crystalized Mercenary, lets the player deal 2 damage to each character in play when, during their turn, a card is put into their inkwell
Strategies like Aristocrats and Soul Sisters both gain small amounts of life constantly during games
Random Spells Cards like Possibility Storm make it so that everyone plays random spells from the top of their library
One of my favorite Sinkhole decks of all-time was Chris Pikulas Deadguy Ale, a B/W land destruction deck with an old-school vibe to it