Take a look at the thermometer/hydrometer from SwitchBot (also available on Amazon). $14 each, but available in packs of 2/4 at a discount.
Nearly all SB products seem to have data export from the app. I have three temp sensors (inside/outside/garage), and also use the smart plug mini to monitor and store power consumption data for devices.
I don't know of a gamified version (but would love to see one), but for help identifying, validating, and tracking sightings you may find the Merlin app from TheCornellLab useful.