The most valuable Gengar cards typically include 1st Edition holographic cards from early sets, Gold Star variants, Alt Art cards from modern sets, and promotional cards with limited distribution
Figure out what your personal metagame is like and run the cards that thrive in that specific environment or just cram in whatever blue instants/sorceries you have on hand and go to town, up to you
Glimmer itself was eminently playable and you can split this card's cost up over multiple turns
Glacial Dragonhunt 0188_MTGTDM_Main: Glacial Dragonhunt A removal spell that doubles as an enabler for your discard theme could be just what you need, as it allows you to disrupt your opponent's game plan and further your own at the same time
This card is very aptly named, prepare for it to spread across all players' battlefields
Each box contains 15 booster packs + 1 Bonus Pack, with every pack guaranteeing a foil card