I used to use the New Tab Override (by Sören Hentzschel). But, Firefox added Security measures which made this Extension obsolete... :(

I was SO HAPPY When I tried this: New Tab Homepage -by Ben Basson !!!

Note: Unfortunately, As far as I know - It can't load or use a local file/custom HTML. (Sorry, people...) It also hasn't been "Recommended" by firefox - Yet... But hopefully it will be, in the near future.

I Use Google as My Homepage, & this extension works perfectly for that...
I simply click on the [+] for a New Tab, & my cursor is already in the Google Search bar! YAY !!!

I Hope This review Helps others in their search for a simple "New Tab Extention"! :)