Namely, most of the flashback and friends cards were created for non-commander formats, and some of the good ones are a nonbo with being copied (Echo of Eons)
It doesn't fly, but if you had dragons die previously, or have milled cards, this can get onto the battlefield for some good effects
Though not legal even for casual play due to their weight and appearance even sleeved, its very easy to tell when youre going to draw a metal card theyre fantastic for collectors
Many of these cards are legendary soldiers that run decks of other soldiers, but many are also soldier type legends that want to run other kinds of decks entirely
Green is good when you need to put lands into the graveyard, my simple solution is a budget land that fetches in Terramorphic Expanse, and the expensive solution is a fetch land like Misty Rainforest