Form, Portal, Grid, & Gallery extensions cannot be shared with the public.

(The workspace owner and collaborators can use the extensions, but they cannot be shared externally on the free plan).

Bulk processor extensions are limited to 10 records (per extension type, per day). Additionally, this kind of extension can only process 1 record per run.

Some extensions are not supported on the free plan (e.g. CSV Exporter).

In your workspace, you are limited to creating only one extension for each type.