Hi there!. Just to leave a straight answer for this (I know someday I will need to find it again). Neutron can display all the amount of floating IP in the pools on each network. You only need to list and see all the IP on the networks with:

 - neutron net-ip-availability-list

If you need to check an specific network on a massive list, you can list and run grep using pipe with the network name.

If you want more info like the project id or the subnet availability (if you have more of 1 pool) you can use the following command:

 - neutron net-ip-availability-show <Network ID>

1. Available for any tenant to take from the the shared pool

   MariaDB [neutron]> select * from ipavailabilityranges ;
   +--------------------------------------+---------------+---------------+
   | allocation_pool_id | first_ip | last_ip |
   +--------------------------------------+---------------+---------------+
   | 41a13f3d-517b-4259-af19-6f4d88edd295 | 30.0.0.16 | 30.0.0.254 |
   | d141f7a6-e548-4921-87a7-6f2c4944574e | 192.168.1.158 | 192.168.1.254 |
   | f78db537-81ae-4dd6-8ecb-467d40467147 | 70.0.0.24 | 70.0.0.254 |
   +--------------------------------------+---------------+---------------+

1. In use (allocated) for particular tenant

   [root@juno01svc ~(keystone_demo)]# nova list
   +--------------------------------------+--------------+-----------+------------+-------------+----------------------------------+
   | ID | Name | Status | Task State | Power State | Networks |
   +--------------------------------------+--------------+-----------+------------+-------------+----------------------------------+
   | b5585e10-86af-4930-9836-504ec461befe | UbuntuRSX001 | SUSPENDED | - | Shutdown | private=70.0.0.13, 192.168.1.152 |
   | 9d0300e5-2f1b-4571-bdaa-9535e8b49d7a | UbuntuRSX005 | SUSPENDED | - | Shutdown | private=70.0.0.21, 192.168.1.155 |
   | a16238b2-2a7f-4984-ae08-60be0a61641f | VF21RSX001 | ACTIVE | - | Running | private=70.0.0.12, 192.168.1.151 |
   | 0d92b906-9d9c-4c50-9c06-e177b959700c | VF21RSX009 | SUSPENDED | - | Shutdown | private=70.0.0.23, 192.168.1.157 |
   +--------------------------------------+--------------+-----------+------------+-------------+----------------------------------+
   [root@juno01svc ~(keystone_demo)]# nova list | awk '{print $13}' | grep -v ^$ | grep -v ^"|"
   192.168.1.152
   192.168.1.155
   192.168.1.151
   192.168.1.157