The Ur-Dragon is currently in the fifth spot of all-time commanders, but I expect that to change with the reprint (theres only a couple hundred decks between it and number four, barely a thousand between it and number three)
in my Hofri reanimator deck, this makes it an enabler for non-deterministic lines and value plays, even when I dont care about the effects of the spell so much
Everflowing Chalice is great in any deck with a Proliferate subtheme
If you're looking to soup up your Wise Mothman Commander deck and don't mind the retro border, you can actually still get a copy of Mesmeric Orb for cheaper than $15
You can activate one loyalty ability of each planeswalker you control during each of your turns, whether that ability is one it always has or the one it gains because of Elspeth's Talent
Most Elementals find themselves aligned with green and red mana but have a good number of cards that are blue and black mana too