iNaturalist is great for logging observations (their iNat Next app is their new one).
They also have an app called Seek that I think is more aimed at kids, but it comes with trophies and streaks and stuff like that.
Seek is impressive just for the sheer number of completely different things it could identify, from mosses to animals. I used it to find native and invasive plants in my garden.
Seek is impressive just for the sheer number of completely different things it could identify, from mosses to animals. I used it to find native and invasive plants in my garden.