What is the best alternative to Halo Collar on iPhone?

Tractive GPS for Dogs and Cats, S tier, #1 in pet tracking.

Is there a free alternative to Halo Collar?

Yes: Tractive GPS for Dogs and Cats (S tier, #1) is free, with no in-app purchases.

Yes. 6 apps rank above it in pet tracking: Tractive GPS for Dogs and Cats (#1), Fi - GPS Dog Tracker (#2), ByteTag (#3) and more.

Halo Collar is C tier, #7 of 8 in pet tracking. Here is everything that competes with it on iPhone, in tier order.

1
Tractive GPS for Dogs and CatsShigher tier
Free · ★ 4.7 · 46,194 ratings · score 96
Companion app for Tractive pet trackers with live GPS location, virtual fences, and activity and health monitoring for…
2
Fi - GPS Dog TrackerShigher tier
Free · ★ 4.6 · 41,720 ratings · score 91
Companion app for the Fi GPS dog collar, showing live location, activity, and behavior trends for a dog.
3
ByteTagAhigher tier
Free + IAP · ★ 4.8 · 9,642 ratings · score 85
Pet identification app for editing contact details and getting notified when a pet's ByteTag is scanned.
4
HeyBuddy ClubAhigher tier
Free download · ★ 4.7 · 2,525 ratings · score 83
Pet ID via digital guest profiles on HeyBuddy tags, plus pet advice, medical records and discounted products.
5
The Pack by ZoetisAhigher tier
Free download · ★ 4.9 · 10,010 ratings · score 81
Pet health and activity tracker with record storage, medication logs, reminders, and a visual diary for pet owners.
6
SpotOn GPS FenceC
Free download · ★ 4.9 · 10,658 ratings · score 69
Companion app for the SpotOn GPS collar that sets virtual fence boundaries and shows your dog's location.
8
Pawscout Pet CommunityD
Free download · ★ 3.6 · 2,273 ratings · score 51
Free pet app for finding lost pets, meeting local pet owners, tracking walks, and browsing pet points of interest.

What is the best alternative to Halo Collar on iPhone?: Tractive GPS for Dogs and Cats, S tier, #1 in pet tracking.
Is there a free alternative to Halo Collar?: Yes: Tractive GPS for Dogs and Cats (S tier, #1) is free, with no in-app purchases.
Does anything rank above Halo Collar?: Yes. 6 apps rank above it in pet tracking: Tractive GPS for Dogs and Cats (#1), Fi - GPS Dog Tracker (#2), ByteTag (#3) and more.