I have been doing this for a while. These are the main ones. There are many that I haven’t listed. Ask, if you need an expertise you don’t see.
PCI Compliance, GDPR, CCPA
SSL certificate purchase and installation (for HTTPS; this is easy, but if you need it, I can do it)
Proxy servers for DDOS attacks, caching, optimizing.
Databases (MySQL, MariaDB, Oracle, MSSQL, Paradox, MS Access, and lots more.)
LAMP server administration (LINUX, Apache, MySQL, PHP)
FEDORA, ELEMENTARY, CENTOS (talk to me–it’s going away), UBUNTU, DEBIAN server set-up and troubleshooting
Command line administration of most LINUX servers
WordPress, Drupal 7 & 8 (and probably 9, but I haven’t been asked yet), Magento 1.9 (talk to me; it’s out of date and vulnerable) and 2.x, CMS systems in general
BiblioCMS (and probably Omeka, but I haven’t been asked, yet)
Gmail administration, WHM, CPANEL, Git, VS