To be fair to Wizards of the Coast, they have shown an appreciation and understanding of the secondary market when it comes to reprints
Heres a look at the most expensive Charizard cards on the market: The Rarest and Most Expensive Charizard Cards Charizard (1999) Base Set 1st Edition Holo For Pokmon collectors and investors, the 1st Edition Base Set Charizard is the holy grail
You run the risk of having your big enchantment blown up without impacting the board, but who runs enchantment removal in Commander
Oko, Thief of Crowns [Best Planeswalker for Permanent Neutralization] Oko s +1 turns any artifact or creature into a 3/3 Elk
Bitterthorn, Nissas Animus Sword of the Animist sees lots of play as colorless land ramp for colors that dont get that kind of effect
A Do Not Bend note on the envelope helps, and for valuable cards, pay for tracking and a rigid mailer rather than hoping a thin envelope survives the sorting machines