Cards like Overlord of the Hauntwoods and Aftermath Analyst should help you get to that prerequisite in no time
Aside from being a human, which is a very relevant creature type in Commander, Modern and basically every other MTG format, Esper Sentinel is good because it reads: Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays X, where X is Esper Sentinels power. Its a bit like Rhystic Study, but the cost can be far higher if youve got things that make humans stronger or you can put +1/+1 counters onto Esper Sentinel
In the right deck, Ramos snowballs into both a gigantic flying attacker and a mana engine that fuels backbreaking turns
Though this doesnt seem that impressive at first glance, bear in mind that, armed with a Rare Candy, you can evolve this Charmander into a Charizard ex on the turn after its played, then power it up immediately using the Charizard exs Infernal Reign