This has become a very popular way to make new mechanics, so let's walk through the different ones Magic has used
Choose your favorite cards, PA your deck, and battle
Najeela, the Blade-Blossom takes a more hands-on approach to its token generation, allowing you to create 1/1 Warriors each time a Warrior attacks
Assemble an army of planeswalkers and use atraxa to add loyalty to them every turn
"Most players on r/EDH have suggested building Kamiz as an Infect deck, which proves their minds are in the gutter." Surprisingly, the average Kamiz deck appears not to be Infect-focused at all, despite the addition of the new Toxic mechanic from Phyrexia: All Will Be One earlier this winter
When someone spend $5 to get a fake copy of Aura Shards instead of $15 to get an authentic copy from their local game store, it cuts into the already tiny margins that most LGSs have to work with