These are all of the userscripts that I have done right now. Most of this is or or will be included in MTurk Suite.
[Mturk Worker] HIT Details Enhancer
Changes the HIT Details link text to the requester name, changes the requester name inside the popup to a link that searches for their HITs and adds the remaining HIT count to the details bar.
[MTurk Worker] Workspace Expander
Expands accepted HITs to fill the browser viewport, scrolls to the HIT and focuses it.
[MTurk Worker] Return All HITs
Returns all HITs that are in your queue
[MTurk Worker] Confirm Return HIT
Prevent accidental returns by adding a prompt when returning a HIT
[MTurk Worker] No HIT Reloader
Reloads pages automatically if no HIT is loaded for provided Group Ids
[MTurk Worker] HIT Exporter
Allows you to export HITs as formatted text with short, plain, bbcode or markdown styling.
[MTurk Worker] Dashboard Enhancer
Brings many enhancements to the MTurk Worker Dashboard.
[MTurk Worker] Auto Accept Checker
Keeps the auto accept next hit checkbox always checked.