Are suggested tags available in all plans?

No. Suggested tags are part of Pro and every plan above it, including Team and Custom plans. Free and Supporter accounts see the Suggested tags entry in the tag menu with an upgrade message.

What each plan gets

Tagging by hand is on every plan, as How do I tag an article? describes. Suggested tags, the AI's proposals for the open article, need Pro. On a Free or Supporter account, Suggested tags still appears in the Article tags menu, and clicking it shows three example tags, "Get suggested tags with our Pro plan!" and Upgrade to Pro. Team and Team Intelligence plans include suggested tags for every member. What are suggested tags? explains how they work.

Suggested tags and Intelligence tokens

Pro includes 1,000,000 Intelligence tokens a month and Team Intelligence 6,000,000, but suggested tags don't use any of them. They keep working when the month's tokens are used up, and they don't depend on the AI platform or the API key chosen under Preferences > Intelligence > Platforms. How many Intelligence tokens are included in the Pro plan? explains what the tokens cover.

Other AI features in Pro

Article summaries, mentions and podcast and video enhancements are part of Pro as well, and Are article summaries available in all plans? has the details for summaries. Intelligence reports are available as an add-on. The Intelligence feature page shows the whole set, and the pricing page compares the plans.