21 cards where (the set is “aer” or the set is “kld” or the set is “klr” or the set is “mps”) and the card types include “elf”

Aether Herder (Aether Revolt #102)
Ajani's Comrade (Aether Revolt #187)
Architect of the Untamed (Kaladesh #143)
Armorcraft Judge (Kaladesh #144)
Cultivator of Blades (Kaladesh #151)
Druid of the Cowl (Aether Revolt #106)
Elegant Edgecrafters (Kaladesh #154)
Ghirapur Guide (Kaladesh #156)
Greenwheel Liberator (Aether Revolt #108)
Highspire Artisan (Kaladesh #157)
Kujar Seedsculptor (Kaladesh #159)
Lifecraft Cavalry (Aether Revolt #113)
Narnam Renegade (Aether Revolt #117)
Peema Aether-Seer (Aether Revolt #119)
Peema Outrider (Kaladesh #166)
Rashmi, Eternities Crafter (Kaladesh #184)
Rishkar, Peema Renegade (Aether Revolt #122)
Sage of Shaila's Claim (Kaladesh #168)
Servant of the Conduit (Kaladesh #169)
Silkweaver Elite (Aether Revolt #125)
Wild Wanderer (Kaladesh #173)

The arc of my blade has carved a path of light to the end of these results.