Overall hardware platform:
4 pcengines alix boxes for openbsd router/firewall appliances
3 supermicro Opteron servers with KVM/corosync/Sheepdog/csync2 for hosting all VMs
Software:
PF + CARP + pfsync + OpenBGPD for routing
Unbound + NSD + Bind for DNS
SSH/OpenBSD ipsec/apache Guacamole for roaming and permanent site-to-site VPN (pcengines ALIX hosted at my inlaws in Japan)
Apache + Lets Encrypt + awstats + relayd for serving web pages and analysis
ZoneMinder for video monitoring. Tied into legacy security system for automation
Postgres for database work. Some mysql/redis
NetDisco + Nagios + NagVis + NFSen + MRTG + Smokeping + PNP4Nagios + NUT + Splunk + Racktables for monitoring. All configs are dynamically generated from netdisco db
OpenSMTPD + Citadel (webcit) for email delivery and webmail
Minetest server for kids. We use this tons as a family, and the kids spend lots of time modding. TW2002 server. TShock server.
OpenELEC for diskless netboot KODI machines around the house
Samba4 Domain controller + NFS for sharing files in different applications
SVN for source control and Config diffs for all servers/tools/network devices
Asterisk via FreePBX / NCID for all phone/CallerID services, including remote handsets at VPN locations
And that's just the ones that I really enjoy using off the top of my head. I hope to find lots more things to try in this thread. Metabase already looks like an awesome candidate!