I like the idea of sending out invitations to my party in the form of cards that let me gain control of other players' creatures
It's not a particularly useful card in a mono-green deck, but Bloom Tender becomes pretty powerful in multi-coloured decks
6 Kefka, Court Mage Players Will Be Dancing Mad When The Clown Enters The Field Discarding can be a major nightmare in Magic: The Gathering, especially when facing something without a lot of drawing power, like a blue deck
Among the expensive FF cards is one that shows an iconic moment from the games, but it's not for everyone
Spot removals: In general I always start my decks with 5 to 7 spot removals for creatures, artifacts, enchantments, counterspells etc
Mirari's Wake faces more competition and interaction these days, but its still powerful