Hey, not a bad idea at all to start some of your side-hustles this way. You'd be surprised, in particularly at how valuable some of these skills are to small and medium businesses.

My suggestions:

MARKETING ADMINISTRATION

- Setting up companies with password tools (e.g. 1Password, Dashlane)
- Organising company files and filing structures (you could do this via Remote Desktop)
- Organising cloud drive systems (OneDrive, Google Drive)
- Installing, updating and managing WordPress Themes and Plugins
- WordPress User Management, Backups

SOCIAL MEDIA

- Setting up social media accounts
- Designing social media backgrounds, thumbnails
- Writing up a social media content plan
- Social media customer support
- Setting up relevant social media streams (for keywords, brand names, competitor names - using something like Tweetdeck or Hootsuite)

EMAIL

- Setting up a mailing list (Mailchimp, Aweber)
- Setting up/designing a monthly email template
- Writing and sending out a monthly newsletter
- Configuring email collection from client website

SEO

Requires a bit of knowledge, but entry level courses will teach you enough for you to offer skills such as:

- Content Optimisation
- Keyword Research

BLOGGING/CONTENT PRODUCTION

- Write X amounts of posts for X amount each month
- Design or find copyright free images to enhance existing content
- Offer proofreading or research services
- Research and produce content calendars

LOCAL MARKETING

- Set up and manage Google My Business, Apple Maps, Yelp and/or TripAdvisor pages
- Set up in relevant local directories or look to secure press in local newspapers
- Local social media (e.g. identifying people who are talking about things locally and follow/engage with them)

PHOTOGRAPHY

- If you've got these skills, take photos and then combine with some of the ideas above (e.g take photos that can be used for social media profiles, within blog content)

Good luck. Let me know how you get on!