Currently self-hosting on an old HP Z600 I bought second hand with the following specs:

• CPU — 2x Intel(R) Xeon(R) CPU X5660 @ 2.80GHz
• RAM — 96GB ECC DDR3 (6*16GB)
• Disks — 4TB HDD for Ubuntu, 10TB HDD for NextCloud and 2TB Sata SSD for Docker

For services, I'm currently running the following:

Docker

• Portainer — CF Tunnel
• FreshRSS — CF Tunnel
• ArchiveBox — CF Tunnel
• Adguard Home — Local
• 2x Uptime Kuma — CF Tunnel
• LinkAce — CF Tunnel
• TheLounge — CF Tunnel
• Watchtower — Local

For public access dockers

• Feedropolis
• Mirotalk SFU
• FiveFilters RSS
• Taiga
• 2x Mattermost Servers
• 8x Wordpress Staging Sites
• 1x Wordpress Dev Sites

For ubuntu, I'm running a few services and apps like:

• ScreamingFrog -9 sites using LAMP stack
• Aria2c with AriaNG
• NextCloud
• Plex
• 4x WebHooks server for communities
• Couple of API end points using Apache reverse proxy
• OpenVPN
• CrowdSec