I think the two most obvious are:
Camelback via Cholla
Piestewa Peak Summit
But there are other peaks around the valley that are worthy alternatives, depending on where you are coming from.
Tom's Thumb
Sunrise Peak (from any of the various trailheads) 128, 124, 145
Peak 2429
North Mountain
Shaw Butte
Daisy Mountain
South Mountain Hikes: Holbert, Warrior, Mormon, Goat Hill via Ranger, Corona de Loma
There may be a couple of others, but I tried to keep them in a reasonably similar range of stats to Echo Canyon.
Please feel free to add others. Over the next 7-8 months (who are we kidding!? ... it won't be done in less than a full year!
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