Not a free solution, but there is an Alfred workflow that enables searching across all the tabs of all the windowsthere is an Alfred workflow that enables searching across all the tabs of all the windows in safari. I just tried it with Safari 13 (after RecentTabList stopped working).
To use it, you have to:
- Download Alfred
- Purchase the Alfred power pack, and then
- Download/import the Search Safari And Chrome Tabs workflow.
I then modified the workflow to use control-tab as a hot key.
It's not as fast as RecentTabList was but it's way faster than searching through 4-dozen open Safari windows and doing a "search open tabs" on each one to find one of your hundred+ open tabs.