VoiceGuy is a great place for resources to help you develop a warm-up for your voice. Here’s where you’ll find the 5 different series that you can access on the site:
Each of these links serves as a short cut to all the steps available on the site.
The Intelligibility Series
The Intelligibility series isn’t a warmup per se, but it can inform your warm up practice and many steps in the series have exercises built into them.