I used to have things in a colo but now I have fiber at home, just about everything is on a single giant machine, complete with graphics card for a gaming VM:

  VM management: libvirt (used to host gaming PC and financial applications)
  Container management: Docker (used to be k8s but gave up)
  Photo gallery: Koken, Piwigo, Lychee
  Media acquisition: Radarr, Sonarr, NZBGet, NZBHydra
  Media access: Plex
  Monitoring: InfluxDB, Grafana, cAdvisor, Piwik, SmartD, SmokePing, Prometheus
  Remote data access: Nextcloud
  Local data access: Samba, NFS
  Data sync: Syncthing
  WireGuard
  Unifi server
  IRC: irssi, WeeChat, Glowing Bear, Sopel (runs a few bots)
  Finance: beancount-import, fava
  Chat: Riot, Synapse (both Matrix)
  Databases: Postgres, MariaDB, Redis
  Speed test: IPerf3

I also have a seedbox for high-bandwidth applications.