SlidesPro - Google Slides add-on w/ shortcuts, YT videos & more
Ludus - Limitless creativity for your slides.
TalkingDeck - With TalkingDeck you can create instructional videos from Google Slides presented by our animated characters.
SlideLizard - Powerpoint plug-in for live audience interaction
Chumpu iMessage Sticker Pack - Animated Chumpu cartoon stickers for iMessage
Zeetings - Turn your presentations into interactive conversations