W Plugin. Does it's job, and does it well. Can open hundreds of Tabs without jumping to 100% CPU, just about 20-30%. However the 100 queue limit is quite steep for my taste, so for others just be ready to go into about:debugging and change the local storage value to fit your queue needs (1000 should be sufficient for most RAM limited mortals)

Excellent! Just what I needed for setting up large reading lists or opening all the tabs I need while I'm debugging. Being able to open a whole folder of bookmarks and not have to worry about slowdown while they load is insanely helpful. Thank you for making this!