The options available are Amber/Amethyst, Ruby/Emerald, and Sapphire/Steel, all containing 60 pre-selected cards of the appropriate pairing that cover the essentials while including a few power players
You dont care if Uro stays on the battlefield or not, youre just using it to get its enter-the-battlefield ability
Probably a bit slow for some older formats, it was just played in way too many decks in Standard
That's why Upheaval is such a bomb: there are virtually no ways to deal with it, and once it is cast you can end up with two to three creatures plus a land on the board while your opponent literally has nothing, and has a hand full of sixteen cards they need to discard down to seven
Thanks to its Rapid Regeneration ability, The Swarmlord enters the battlefield with two +1/+1 counters for each time you've cast your commander from the command zone