Bug overview description.
it isn't possible to use the after_id parameter and paginate through that mechanism because it returns the tags in an unsorted manner.

What part(s) of the site page(s) are affected?
The tags api

What is the expected behavior?

I'd assume that it would return sorted tags, as that's nearly required to replace pagination.

What actual behavior is given instead?
For example, if you set after_id=1 to (presumably) get the first tags you get tags with ids like 12054.

Can you reproduce the bug every time?
Yes, it's fairly consistent.
What steps did you take to replicate this bug?
I navigated to https://e621.net/tag/index.json?after_id=1&order=date

It appears that tags are sorted in descending order when using date/created order, which isn't very helpful for after_id. I'll have after_id forcefully sort in ascending order to fix the results.

I appreciate your help for this.