Now is the perfect time for you to dive into your first Magic game
If the creatures are too much to handle, it's good to use the creature destruction effect, and if the battlefield is manageable, destroying all lands is the way to go
Imposter Mech is an excellent card, though not nearly as good as the others
Rules-wise, theyre a seperate creature type , so there are dragon cards and drake cards
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