Black/Green: Graveyard Black and green are sticking to the old Golgari classic: graveyard decks
They only cost anywhere between one and three mana, and they'll stay on the battlefield until destroyed, bounced, or sacrificed
The discard effects are what you want to zero in on here, with a notable one being the combination of Nath with Sadistic Hypnotist to Mind Twist your opponents
Knowing when to quest, when to challenge, when you use your actions, etc
Selesnya decks are typically all about life gain and steadily growing creatures through the use of counters, and while the counter aspect is present on T'Challa, the life gain aspect is currently missing
About the only thing that'd make this card better would be somehow giving all those Dragon Elementals haste