Read the animal before you touch anything
A reptile out of place, in a garden, a park, a stairwell, is most likely an escaped or released pet, frightened and cold rather than dangerous, but your first job is assessment, not rescue. Stop at a distance and take in what you are looking at: how big is it, how is it moving, is it injured, is it a species you genuinely recognise? A tortoise plodding across a lawn and a bearded dragon flattened on warm paving are animals most people can help directly. A snake is a different calculation. If you cannot name it, or it is large, keep your distance and skip straight to calling for experienced help; there is no version of this story where reaching for an unknown snake ends well.
Containing the animals you can help safely
For a tortoise, lizard or small, clearly harmless animal, a sturdy box with air holes and a lid that can be secured is the whole capture kit. Line it with plain paper, coax a lizard in with a towel used as a gentle guide rather than grabbing at it, and lift a tortoise with both hands, supporting it fully, because a dropped tortoise is a cracked shell. Work calmly and expect the animal to be stronger and quicker than it looks. Wash your hands thoroughly afterwards, as you should after handling any reptile, since reptiles can carry salmonella without being ill themselves. If the animal is injured, bleeding or limp, contain it exactly the same way but treat the vet call as urgent.
Warm, dark and quiet while you arrange help
A found reptile's immediate needs are boring ones: a box in a warm room, away from your own pets and from curious children, with a towel over part of it to give darkness and a sense of cover. Do not offer food, because you do not know the species' diet or when it last ate, and a shallow dish of water is enough for a tortoise or lizard while it waits. Resist the urge to keep checking on it with an audience; every opening of the box is a stress event for an animal that has already had a bad day, and a quiet hour in the warm is worth more than any amount of well-meant handling.
Who takes it from here
Your calls go to the people equipped to receive it: a local reptile rescue, an exotics vet, or the animal warden service in your area, any of whom will either take the animal or tell you exactly who will. It is also worth checking local lost-pet groups and notices before assuming abandonment, because many found reptiles are escaped pets whose owners are searching a street away, and a description shared locally can end the story in an afternoon. If the animal turns out to have been deliberately released, the rescue will know the local picture and what happens next.
Finding that help quickly matters more than finding it perfectly, and KinsLe's Pet Services Directory exists for exactly this moment, letting you locate a trusted local exotics vet or reptile rescue near you and connect with them straight away.