rfair404

In the multisite context, creating widgets that are used throughout all of the sites in a network can be difficult and painstaking (at best). 
This plugin gives network administrators the ability to create “fallback widgets” that will be used as the default unless over-ridden by individual sites.
How the plugin works
<ul>
<li>When a widget is created on the “main site” (e.g. site ID 1) the output is cached.</li>
<li>When a sites other than the “main site” (e.g. site ID != 1) call a sidebar that doesn’t have any active widgets, the cached output from the main site will be used.</li>
<li>The plugin may not (read as “probably won’t”) work with highly dynamic widgets</li>
<li>This is the initial release, so please try it out before you use it in a live site.</li>
</ul>

Network Sidebar Widgets

Enables Multisite Networks to create "fallback" widgets that can be used across-network when sites don't have any widgets.

Ipstenu (Mika Epstein)

JohnnyWhite2007

Spam is one thing, but trolls and sock puppets are another. Sometimes people just decide they’re going to be jerks and create multiple accounts with which to harass your honest users. This plugin helps you fight back by logging the IP address used at the time of creation.
Log into your WP install as an Admin and you can look at their profile or the users table to see what it is. For security purposes a user’s own IP is not displayed to them when they look at their own profile.
<ul>
<li><a href="https://ko-fi.com/A236CEN/" rel="nofollow ugc">Donate</a></li>
</ul>
<h3>Privacy Notes</h3>
This plugin adds additional data to a new user’s <code>wp_usermeta</code> data under the <code>signup_ip</code> key. This data is directly tied to the user account, and is only editable via the database. Should a user account be deleted from the site, the data will be automatically deleted.
No external data is transmitted, it all stays on your install.

Register IPs

Does exactly waht it says

When a new user registers, their IP address is logged. Supports multisite and single site!

Network Sidebar Widgets vs Register IPs