For starters, the ability to get a second use out of your most effective spells is great, but it also removes the extra cost you normally have to pay with flashback cards
Kaya, Geist Hunter Crimson Vow s Kaya, Geist Hunter costs 3 mana and can activate its second loyalty ability as soon as it drops, doubling the number of tokens you create until the end of the turn
While the extra ability on this sounds weird, the best thing it does is remove combat-related keywords like deathtouch and first strike
Dragonwing Glider Expensive MTG equipment with a very high equip cost isn't usually good, but Dragonwing Glider changes the equation by creating a token to snap onto right away
Commander / EDH / Vampires MTG Decks a tribal deck, often with a lifegain element, that uses Vampire creatures like Vampire Nighthawk and Forerunner of the Legion