Because indestructible cards cant be destroyed by any effects which use the word destroy on them, they are not affected by cards which say, destroy all
Mass of Mysteries, from Lorwyn Eclipsed Commander , is arguably the weakest of the give myriad to other cards, but it's still very good when giving myriad to elementals with strong enters effects, like Mulldrifter
However, sets like Crown Zenith and Shining Evolution, which are both no longer in circulation and have valuable chase cards, are also profitable
Remember how 2000's winner Lin Sivvi dominated by abusing the legend rule at the time, when only one copy of a legend could be on the battlefield
Baffling End is also a nice way to clean up Adanto Vanguard
Deathrite Shaman would often take control of a game on its own, and all at the low cost of a single mana