Stand AloneTemp sensor modules?

I think I saw… in a video a hint for a stand alone temperature ( and humidity ? ) sensor. If the sensor was a WiFi direct without a bridge, and battery OR wired power I could place in my garage ( I winter pets and plants ) and also in 2 outbuildings ( one is a greenhouse) on my property. Even battery powered, periodic reporting would be adequate. Upper/lower alarms. I could also replace an indoor/outdoor Bluetooth that reports to a display terminal for my refrig/ and separate freezer. I’m using power line tech to reach far points reliably and have ordered TUYA technology to test this approach until WYZE tech becomes available .

**//Mod Edit: Title Modified to Enhance Search Clarity.

I would add that I need this for monitoring cold spaces in my house for potential frozen pipes and/or high humidity damage to certain items stored in those spaces.