Landed on 172.16/22 for this reason however it's not uncommon how an enterprise to use all 3 private classes. One place I worked used 192.168 for management, 10 for servers, and 172 for wifi
Using 2 different classes has been a pretty common setup for wifi and wireless in my experience
There's numerous other reserved IPv4 blocks that can be used: https://en.wikipedia.org/wiki/Reserved_IP_addresses#IPv4. Would definitely not recommend to use 10/8 for private networks.