I like a lot of the big red spells but Thieves' Auction is probably my favorite especially when you can break parity with something like t-pro or Worldgorger Dragon, similarly to MLD
A collector may deem a card valuable if its from an older set, if it contains nostalgic value for them, or if its increasing in monetary value over time
There are hundreds, really, but my favorite has always been Battered Golem plus a 0-cost artifact and Retraction Helix/Banishing Knack
instead, it phases out at a given point and later phases in, usually during the next untap step
Voja's always the commander of your elf + wolf deck rather than a member of the 99 anywhere, as theres no way you fit a Naya card in traditional G or BG elf decks
Speaking of discarding, there will be plenty of opportunities to discard in Amonkhet , right around the corner