One of the easiest ways to get myself into the Zigbee life without needing to worry too much about exactly what I was doing, buying or what my goals were was to buy a set of Temperature and Humidity Sensors for every room of the house.
After a tiny amount of research and some discussion among friends, I settled on a fleet of Aquara sensors. These work well with home assistant, use batteries that I have many of already and want to use up, are visually appealing and can be bought in bulk on AliExpress.
For a hub, I went for the SMLIGHT SLZB-06 that has some good reviews in terms of flexibility and openness, as well as allowing use via wired network, Wi-Fi or even USB.
Everything was extremely easy to set up, wiring the hub into the network and having it appear in Home Assistant running on my Raspberry Pi 4, and then pairing each of the sensors with the Hub and having them appear within Home assistant.