I don't know if the foldable elements are documented elsewhere, but the "folding" is done in the functions org-hide-block-toggle-maybe and org-hide-block-toggle (the former just calls the latter and ignores errors). The list is as follows:
(center-block comment-block dynamic-block example-block
export-block quote-block special-block
src-block verse-block)
Instead of using #+RESULT for this (which is specifically meant for results of source blocks), I would use an example block:
#+BEGIN_EXAMPLE
#+NAME: TBL
| Foo | Bar |
#+END_EXAMPLE
I tried to find an org version that actually folds #+NAME (or #+TABLE) elements and I couldn't come up with one, although I went back five years to version 8.1 (of course, I could have made a mistake). Are you sure that this was ever the case? If so, what version of org-mode (M-x org-version will tell) was that?
UPDATE: org-hide-block-toggle is used for blocks, but not for results. Results are handled through the org-tab-first-hook variable: ob-core.el adds org-babel-hide-result-toggle-maybe to the hook and that is what folds/unfolds results. AFAICT however, that is not used for #+NAME folding - still looking.