The Elisp manual section on Special Forms (10.2.7) lists around two dozen
special forms, but two of them aren't special forms.

* `lambda', it turns out, is not a special form, but a macro that wraps
itself in a call to the special form `function'. (The documentation for
`lambda' refers to it as "self-quoting"; this might be better changed to
"self-evaluating".)

* `track-mouse' isn't a special form, but a macro wrapper around the
primitive function `internal--track-mouse', which isn't a special form
either. (Section 29.15 on Mouse Tracking also inaccruately refers to
`track-mouse' as a special form.)

On the other hand, the special form `inline' is not listed in the Special
Forms section.

A list of all special forms can be gotten with

(let (special-forms)
  (mapatoms
   (lambda (sym)
     (when (special-form-p sym)
       (push sym special-forms))))
  (sort special-forms #'string<))