Please provide option to define user tags (labels) for items (triggers, hosts, alerts, ...). They will be only metadata used for selecting - for example env = prod, tier = t1, name = db*. Tags will be useful for 3rd party tools - Grafana (API filtering by tag must be implemented as well).
It'll be awesome, if also agent can send tags with item value and zabbix-server will store them - for example fs util = 50% tags[fs=tmp] (see OpenTSDB metric tagging). LLD won't be needed, but more sophisticated UI will be required (querying with the tags).
It'll be useful for many products, where tagging is already used - see AWS, Kubernetes, ....