In Japan and Asia, BT-05 is a relatively successful attempt from Bandai to diversify meta decks.
Prior to BT-05, the meta landscape is predominantly a "Christmas Tree": Yellow Wargreymon and Green Nidhoggmon. Back then, the yellow Wargreymon deck had so much synergy that it became one of the most effective aggro decks. Meanwhile, the green Nidhoggmon deck has enabled such a strong board-wipe for counterattacks that has allowed for comebacks at almost any situation.
Moving on to BT-05 Battle of Omega (which we think is the most valuable set so far), which had the most expensive box-topper (Nokia Shiramine), multiple alternative arts for a single Omegamon (4 parallel arts), commanding a high price until today, a classic art AA Omegamon X-antibody, and a steadily-priced Omegamon Zwart-Defeat (that is still increasing today). This is also the expansion where paired-art card concept started (not counting BT-04 since that's a one-off triplet), and the last booster set that does not include block icon on the cards.