How do I title a section pertaining to "things I can do" on my CV?

Solution 1:

While one could argue that they are synonyms, I think Expertise and Skills work well together. Or, better yet, Expertise and Strengths. If you need an additional heading for the applications you work with, try Tools.

strength, n. 13. An aspect in which a person or thing is strong or strongest; a powerful or beneficial attribute or quality, a strong point.

skill, n.¹ 6. a. Capability of accomplishing something with precision and certainty; practical knowledge in combination with ability; cleverness, expertness. Also, an ability to perform a function, acquired or learnt with practice (usually plural).

expertise, n. (b) The quality or state of being expert; skill or expertness in a particular branch of study or sport.

_{Source: Oxford Englsih Dictionary (login required)}

Expertise

• Logos & Branding
• Technical Drawings
• Pitch Decks

Strengths

• Planning and Organising
• Verbal Communication
• Visual Communication

Tools

• Illustrator
• CAD
• PowerPoint

Solution 2:

They're still Skills or Key Skills.

In an American resume, these items would most likely be grouped under Skills, which would be a catch-all for the things you can do. For instance, The Muse advises creating individual headers under Skills for each field or area of expertise you want to emphasize. For example:

Visual Design: InDesign, Illustrator, Photoshop, After Effects, Premiere, XD, Animate, Lightroom

3D Modeling & 2D Drafting: Rhino, VRay, AutoCAD, Vectorworks, Autodesk Fusion 360

First, note the use of subheaders. If you already have Key Skills, you can develop two or more subheaders. For example, you could label "Leadership" for the interpersonal bits and "Communication" or "Design" for the genres you do. If you go this route, the number and names of these subheaders are personal to you.

The previous example's list was largely software / tool-based. However, the usage of Skills is expansive and can include soft skills and common genres as well. Here's an example from Career Sidekick, deformatted into a comma list:

Phone sales, In-person sales, Lead generation/prospecting, Qualifying leads, Sales presentations, Sales team leadership/training, Customer service, Client on-boarding, Client relationship management

This list is commonly genres (sales presentations) and tasks (qualifying leads), rather than tools.

It is also an example of someone who lumped them together rather than using subheaders, showing that multiple approaches may be valid. Even the section title can vary based on the individual resume/CV writer (I've seen Skills and Certifications, for instance, as well as your own Key Skills), and many resumes and CVs choose to emphasize skills exclusively through work experience and project sections. So beyond knowing that this individual usage (Skills) exists, I would ask multiple people in your field and country what they do.