That’s a pretty cool find! I think you’ve got a gray tree frog there rather than a toad. The big toe pads and that mottled gray coloring are a pretty good giveaway.
Finding it tucked away under the tree makes sense, too. They’re surprisingly good at disappearing into leaf litter and vegetation. I’d definitely consider that a good sign for the garden - one more little predator helping keep the insect population under control.
I’d leave him right where you found him and let him get back to his hiding spot. Definitely a much nicer discovery than another garden pest!