25 cards where the color identity ≤ RUW and (the card types include “ally” or the text includes “ally”) and the mana value < 3 and the text doesn’t contain “rally” and it’s legal in Commander

Akiri, Line-Slinger (Commander 2016 #26)
Captain's Claws (Oath of the Gatewatch #162)
Stone Haven Outfitter (Oath of the Gatewatch #37)
Ally Encampment (Battle for Zendikar #228)
Jwari Shapeshifter (Worldwake #32)
Ondu Cleric (Zendikar #30)
Halimar Excavator (Worldwake #29)
Hada Freeblade (Worldwake #7)
Kazandu Blademaster (Zendikar #16)
Expedition Envoy (Battle for Zendikar #24)
Serene Steward (Battle for Zendikar #46)
Akoum Battlesinger (Worldwake #71)
Highland Berserker (Zendikar #132)
Weapons Trainer (Double Masters #228)
Coralhelm Guide (Battlebond #116)
Cliffside Lookout (Battle for Zendikar #20)
Zada's Commando (Oath of the Gatewatch #120)
Stoneforge Acolyte (Oath of the Gatewatch #38)
Makindi Aeronaut (Oath of the Gatewatch #27)
Umara Entangler (Oath of the Gatewatch #65)
Ondu War Cleric (Oath of the Gatewatch #31)
Reckless Cohort (Battle for Zendikar #152)
City in a Bottle (Vintage Masters #265)
Apocalypse Chime (Homelands #101)
Kor Castigator (Battle for Zendikar #35)

Though this query has ended, its relics still slumber in New Argive.