之前有回复过类似的功能，用 ivy 实现了一个特性。
主要的使用场景是插入概念性的笔记。因为这些笔记的层级关系太过明显。缺点 是，时间久了以后，流畅性还是不足。
Helm 有可以把多种搜索后端整合到一起的功能，如果把单个大文件单拿出来， 以 headline 搜索为结果，并入到 helm 的 org-roam-find-file 也许是一个不 错的选择。
(setq-default wr--head-var-a "headline name")
(defun wr/counsel-outline-action (x)
(setq wr--head-var-a (car x)))
(defun wr/counsel-outline ()
(interactive)
(let ((settings (cdr (assq major-mode counsel-outline-settings))))
(ivy-read "Outline: " (counsel-outline-candidates settings)
:action (or (plist-get settings :action)
#'wr/counsel-outline-action)
:history (or (plist-get settings :history)
'counsel-outline-history)
:preselect (max (1- counsel-outline--preselect) 0)
:caller (or (plist-get settings :caller)
'wr/counsel-outline))))
(defun wr/insert-a-head-from-a-file (x)
(interactive)
(xref-push-marker-stack)
(save-restriction
(save-excursion
(with-ivy-window
(pcase (cdr x)
(`(:path ,foo :title ,bar) (progn
(with-temp-buffer
(erase-buffer)
(insert-file-contents foo)
(call-interactively #'wr/counsel-outline))
(insert (format "[[file:%s::*%s][%s]]" foo (car (last (split-string (substring-no-properties wr--head-var-a) " → ")))
(string-trim-left (car (last (split-string (substring-no-properties wr--head-var-a) " → "))))))))))
(message "A head has been inserted.")
(xref-goto-xref))))
(ivy-set-actions
t
'(("h" wr/insert-a-head-from-a-file "insert")))