If you go to the home page of ArcScripts you are greeted with this message:
ArcScripts are Moving
We at ESRI thank you all for your valuable contribution to ArcScripts
over the years. This Web site has been most valuable for the user
community to share a multitude of tools; however, this application has
become outdated. We have brand new Code Galleries that are part of the
new ArcGIS Resource Center.
As of April 2nd, 2010, ArcScripts is closed for all new scripts and
edits to existing content; however, we will keep them read-only for at
least several years. The direct URLs for ArcScripts and individual
scripts will remain available, and the content throughout will be
searchable from the new ArcGIS Resource Center.
If you have new scripts, or updates to existing scripts, we invite you
to try the new Code Galleries.
If you click the new Code Galleries link you will reach:
We're in the process of reorganizing.
The page you were looking for has moved or no longer exists.
In 15 seconds you will be redirected to a list of current content
organized by product, industry, or developer platform. Choose a
specific community or search to find the information you need.
Once you find the resources relevant to you, please update your bookmarks.
Waiting 15 seconds does redirect me to the Communities page
If I am after a Python script tool I click the Python link to reach the Python for ArcGIS page which does have a Gallery where you can see and choose items.
Where it becomes more cryptic is when you decide you want to upload something. I spotted a More Gallery Posts link which I followed to find a What types of items can I find here? which I followed to find out that I was actually in ArcGIS Online:
What can you add to ArcGIS Online?
The following list shows which types of maps, layers, apps, tools, and
files you can add to ArcGIS Online through My Content. You must have
privileges to create items to add them to ArcGIS Online.
This not being simply a link from the ArcScripts page makes me think that what was advertised as a move was the start of a deprecation of its original and much loved concept.
You will find an Add Items link in the sidebar and if you follow that too then it becomes even more evident that you are in the embrace of ArcGIS Online.
As an alternative you could try searching and contributing to ArcGIS repositories at GitHub.