I haven't used them with garters, but I did feed Xenopus to a southern hognose with out ANY ill affects what so ever (it's all I could get the little buggar to eat!). I know of others that have done the same. Having said that, I wouldn't recomend feeding any live amphibians to your garters, mainly because they are host to lots of different parasites. As far as lizards go, I keep geckos in my freezer to occasionally supplement the diets of my Thayeri kings and also to get the hatchlings to feed. If you can get frozen anoles or geckos, I think it'd be worth a try to give it to garters and see if they will take it.