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
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
However, sets like Crown Zenith and Shining Evolution, which are both no longer in circulation and have valuable chase cards, are also profitable
This format is perfect for players who want to stay up-to-date with the latest cards and strategies
Even from the battling side, one of the most fun things about the physical TCG is the effort it takes to build a deck and play that deck well