If what you mean is actions that can be triggered from the context menu of the file manager, after selecting one or more files or folders, I don't know if the proper name is "extensions", but
.contract files can be created in
usr/share/contract to add context menu entries to Pantheon-Files.
So, the general answer to your question is "Yes". But if you mean whether you can find ready-made
.contract files on the internet to download and use, the answer is rather negative.
About mentioning all of them:
I suppose the list you get in Nautilus with the command you mention is the list of scripts/extensions that are already installed.
To see the one present in Pantheon Files take a look in
As said in a comment, there is no exhaustive list for these context-menu actions: first, because, as far as I can tell for the moment, there are no such ready-made
.contract files to be found on the internet available for download, as you have for Nautilus or Thunar; second, as they can be created for the specific commands that you want applied to different files or folders, they are too many to list, because they are as many as the possible applicable commands that may involve different executable files/scripts.
About mentioning a few of them:
Some of the ones I have used: some to play/open in different programs, to convert, to extract audio without conversion, to display media info or mime-type, to run an executable file, to search, to join... Most of these are mentioned on this site or on U&L stackexchange. (For example: here, here, here or here; also: here). If you need a certain context-menu action in Files, you can search on such sites or post here a question asking for that.
To create a new one the procedure is something similar to the following one, an example which adds a search option with Catfish:
gedit as text editor:
Exec=catfish --path=%f %U
Save and close text editor.