: Add 
or 
.Hinterland Harbor supports green-blue decks by supplying either color from one land. It enters untapped when you already control a Forest or an Island, so its performance depends on the types represented by your earlier land drops. A basic or a typed nonbasic can satisfy that requirement. This makes it particularly useful after the first turn, when the mana base has begun to establish itself.
Breeding Pool is a useful partner because its basic land types can enable the untapped entry. Misty Rainforest can find that shock land or an appropriate basic first, setting up a later Hinterland Harbor. Sequencing those sources in the right order can preserve mana for development and interaction without paying life for this land itself.
For ramp and landfall strategies, the practical benefit is choosing between spells such as Three Visits and Counterspell as the turn develops. Green acceleration can establish the board before blue draw and interaction take over. Aesi, Tyrant of Gyre Strait rewards land entries, while Lotus Cobra can make a developing mana base produce additional resources immediately. A flexible source supports those decisions without requiring a separate fixing artifact to stay on the battlefield.
The entry check uses land types rather than names or the colors a land happens to produce. Hinterland Harbor has no basic land types of its own, so a fetch land cannot search for it. An opening hand built only from lands with similar conditions may start slowly. Keep enough reliable first-turn sources to make the condition easy to meet.
