iquark

YouTube Playlist show the list of videos of a given YouTube’s playlist ID.
You can choose to use it by widget or by a shortcode. There is an example if you whant to do it by the secon option:
[youtube_playlist id=”PL335DD2E2EE782021″ maxResults=”2″ thumb_size=”small” class=”youtube_playlist”]
The parameters are all optional: 
 * id: is the playlist’s ID, you can put it in either starting by PL or not, it has a default value, but is interesting you put yours :P. 
 * maxResults: the maximum number of videos to show, by default “2”. 
 * thumb_size: you can show the thumbnail “small” or “big”, by default “small”. 
 * class: you can change the class of the list by one who is better for you (in case you need it), by default “youtube_playlist”.

Youtube Playlist

YouTube Playlist show the list of a given YouTube's playlist ID.

UjW0L

This plugin lets you to display Youtube widget on sidebar with the themes that supports sidebar and Footer
It displays video and playlist of your choice with video id and playlist id. 
It also lets you display all videos from you youtube channel with option to navigate to next nd previous button. 
No google API key needed. Uses Youtube rss feed.
You have choice between single video , playlist and channel.
Note:

Simple Youtube Widget

Plugin that provides users option to display Youtube Widget on the Sidebar or Footer

Youtube Playlist vs Simple Youtube Widget