Hello Adalberto,
There is no dedicated agent for VIOS, but you can use the agent for AIX.
To monitor VIOS-specific items, you can use "user parameters" and use your own scripts or one-liner (https://www.zabbix.com/documentation/current/en/manual/config/items/userparameters)
Zabbix is quite popular, but I haven't found anything ready-made on the web for VIOS monitoring, so I think I could prepare an article on this topic in my free time.
Example "user parameters" might look as follows:
UserParameter=entstat.sea.hamode[*],entstat -d $1 2>/dev/null | grep "High Availability Mode" | awk '{print $$4}'
UserParameter=entstat.sea.state[*],entstat -d $1 2>/dev/null | grep " State:" | awk '{print $$2}'
UserParameter=entstat.sea.lacp_out_of_sync[*],entstat -d $1 2>/dev/null | grep "OUT_OF_SYNC" | awk '{print $$2}'
You can create Template in Zabbix GUI with items and triggers dedicated for VIOS, related to the "user parameters".
It's good to create "Discovery" with items prototypes, expecially if you have multiple adapters (https://www.zabbix.com/documentation/current/en/manual/discovery/low_level_discovery/item_prototypes)