magic the gathering march of the machine collector booster box Machine: Aftermath Leaks 1 oversized Spindown life counter MTG: March of the Machine

Especially when one of the markets is white hot like Pokmon is right now

This gives it some advantages compared to both of its counterparts, since you're not capped at only a single copy, and playing it doesn't use up your single chance to play a supporter in a turn

Unique Stellar Tera crown design Rarer than many other SIRs based on current listings 6

While some of these are getting harder to find, you can still do so

All still provide one of the most efficient and immediate returns on cards for the mana and still see occasional use but with most decks being more traditional agro, midrange and control these cards are too risky and too symmetrical to be appropriate very often

Oh, and a shout out to Magus of the Wheel which was my #13 initially but had to get pulled off in the numbers, sorry