Some of the 3.5" ones come without fans (a bad idea in my opinion) so they are as quiet as the drive. There''s a pretty good selection
here but if you Google for "external enclosures" or something like that you can find tons more.
Most enclosures that use a fan come with a 40mm x 10mm fan which is a standard size. You can swap them out for a quieter fan (Sunon makes some fairly quiet 40x10mm fans) and you can also do the "7-volt mod" to them.