The one it comes with.
Pulling down GIFs from an external site means you’re decreasing the security posture of yourself and the recipient by at least one third party.
Personally, I keep all GIFs filtered in all messaging systems and discussion pages. They add little, and beyond usually being privacy invasive, can also be a security concern.
The crazy thing to me is that this is the conclusion I came to around 30 years ago, based on evidence that was already present in research available at the time.