Eclipsed Boggart

Cast it off pure black, pure red, or any mix, and this slots into a Goblin shell no matter which of its two colors that shell actually runs: the flexible pips are doing double duty as an inclusion permit. The selection is deliberately narrow. It digs four deep but only ever surrenders a Goblin, a Swamp, or a Mountain, which makes it a tribal enabler and a land-smoother in the same slot. A Goblin deck short on gas finds another body; a two-color deck stuck on colors finds the land it needs. The misses go to the bottom in random order, so unlike a scry effect it offers no ordering of what you leave behind, only the single hit you pull forward. The 2/3 body is built to survive the early turns rather than trade into them, holding ground while the card it dug for turns into pressure. It belongs to a long line of enters-the-battlefield selection creatures that pay for their dig with an unremarkable rate, but the constraint here is tighter and more purposeful than the usual open-ended look at the top four: three narrow card types is the entire menu, which is why the effect reads as a tribal-and-fixing engine rather than raw card advantage. That restriction is the point, not a limitation grafted on afterward.